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RRB Group D study materials
RRB Group D study resources

RRB Group D practice questions

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Question 1Mathematics

Simplify: 12 + 6 ÷ 3 × 2 − 4

  1. 12 Correct answer.
  2. 16
  3. 8
  4. 10

Explanation

BODMAS requires division and multiplication to be done before addition and subtraction, working left to right. So 6 ÷ 3 = 2, then 2 × 2 = 4, giving 12 + 4 − 4 = 12.

Question 2Mathematics

What is the highest common factor of 24 and 36?

  1. 72
  2. 6
  3. 24
  4. 12 Correct answer.

Explanation

Both numbers factor as 24 = 2³ × 3 and 36 = 2² × 3², so the HCF is 2² × 3 = 12. It is also the greatest number that divides both 24 and 36 exactly.

Question 3Mathematics

Find 15% of 400.

  1. 60 Correct answer.
  2. 65
  3. 45
  4. 40

Explanation

A percentage of a quantity is found by multiplying the quantity by the rate over 100. Here 400 × 15/100 = 400 × 0.15 = 60.

Question 4Mathematics

Find the average of the first five even natural numbers 2, 4, 6, 8 and 10.

  1. 6 Correct answer.
  2. 5
  3. 10
  4. 30

Explanation

The average of a set of numbers is their sum divided by how many numbers there are. The sum is 2 + 4 + 6 + 8 + 10 = 30 and there are 5 numbers, so the average is 30 ÷ 5 = 6.

Question 5Mathematics

Find the simple interest on 5000 at 10% per annum for 2 years.

  1. 1200
  2. 500
  3. 1000 Correct answer.
  4. 1100

Explanation

Simple interest is calculated as SI = (P × R × T)/100. Substituting gives (5000 × 10 × 2)/100 = 1000.

Question 6Mathematics

What is the value of √1764?

  1. 38
  2. 44
  3. 42 Correct answer.
  4. 46

Explanation

The square root is the number whose square is the given number. Since 42 × 42 = 1764, the square root is 42.

Question 7Mathematics

Divide 240 into two parts in the ratio 3 : 5. What is the smaller part?

  1. 120
  2. 150
  3. 80
  4. 90 Correct answer.

Explanation

The total number of parts is 3 + 5 = 8, so one part equals 240 ÷ 8 = 30. The smaller share is 3 parts, that is 3 × 30 = 90.

Question 8Mathematics

Which of these fractions is the greatest?

  1. 5/8
  2. 3/5
  3. 7/12
  4. 2/3 Correct answer.

Explanation

Convert each fraction to a decimal to compare: 3/5 = 0.6, 5/8 = 0.625, 7/12 ≈ 0.583 and 2/3 ≈ 0.667. The largest decimal value is 0.667, so 2/3 is the greatest fraction.

Question 9Mathematics

An article bought for 480 is sold for 552. Find the profit per cent.

  1. 20%
  2. 18%
  3. 13%
  4. 15% Correct answer.

Explanation

Profit = 552 − 480 = 72, and profit per cent is always taken on the cost price. So profit % = (72/480) × 100 = 15%.

Question 10Mathematics

A can finish a piece of work in 12 days and B in 18 days. Working together, in how many days will they finish it?

  1. 6 days
  2. 7 1/5 days Correct answer.
  3. 7 1/2 days
  4. 8 days

Explanation

In one day A does 1/12 and B does 1/18 of the work, so together they do 1/12 + 1/18 = 5/36. The time taken is the reciprocal, 36/5 = 7 1/5 days.

Question 11Mathematics

A car covers 240 km in 4 hours. At the same speed, how far will it travel in 7 hours?

  1. 380 km
  2. 450 km
  3. 400 km
  4. 420 km Correct answer.

Explanation

Speed is distance divided by time, so the car travels 240 ÷ 4 = 60 km each hour. In 7 hours it covers 60 × 7 = 420 km.

Question 12Mathematics

Find the compound interest on 8000 at 10% per annum for 2 years, compounded annually.

  1. 1720
  2. 1680 Correct answer.
  3. 1600
  4. 1650

Explanation

Amount = 8000 × (1 + 10/100)² = 8000 × 1.21 = 9680. The compound interest is the amount minus the principal, that is 9680 − 8000 = 1680.

Question 13Mathematics

A father is three times as old as his son. After 12 years he will be twice as old as his son. What is the son's present age?

  1. 16 years
  2. 12 years Correct answer.
  3. 14 years
  4. 10 years

Explanation

Let the son's age be x, so the father is 3x. After 12 years, 3x + 12 = 2(x + 12), which gives 3x + 12 = 2x + 24, hence x = 12.

Question 14Mathematics

The speed of a boat in still water is 10 km/h and the speed of the stream is 2 km/h. How long will the boat take to go 24 km downstream?

  1. 2.4 hours
  2. 2 hours Correct answer.
  3. 3 hours
  4. 1.5 hours

Explanation

Downstream the stream helps the boat, so the effective speed is 10 + 2 = 12 km/h. Time = distance ÷ speed = 24 ÷ 12 = 2 hours.

Question 15Mathematics

Solve for x: 5x − 7 = 3x + 9

  1. 16
  2. 6
  3. 8 Correct answer.
  4. 4

Explanation

Collect the x terms on one side and the numbers on the other: 5x − 3x = 9 + 7, so 2x = 16. Dividing both sides by 2 gives x = 8.

Question 16Mathematics

The perimeter of a rectangle is 60 cm and its length is 18 cm. Find its area.

  1. 180 cm²
  2. 240 cm²
  3. 200 cm²
  4. 216 cm² Correct answer.

Explanation

Perimeter = 2(length + breadth), so 60 = 2(18 + b), giving 18 + b = 30 and b = 12 cm. Area = length × breadth = 18 × 12 = 216 cm².

Question 17Mathematics

Find the LCM of 12, 15 and 20.

  1. 60 Correct answer.
  2. 120
  3. 30
  4. 180

Explanation

Write each number in prime factor form: 12 = 2² × 3, 15 = 3 × 5 and 20 = 2² × 5. Taking the highest power of each prime gives 2² × 3 × 5 = 60.

Question 18Mathematics

The price of a book rises from 250 to 300. Find the percentage increase.

  1. 16.67%
  2. 50%
  3. 25%
  4. 20% Correct answer.

Explanation

Percentage increase is the increase divided by the original value, multiplied by 100. Here the increase is 300 − 250 = 50, so the increase is (50/250) × 100 = 20%.

Question 19Mathematics

Pipe A can fill a tank in 6 hours and pipe B in 4 hours. If both pipes are opened together, how long will the tank take to fill?

  1. 2.5 hours
  2. 5 hours
  3. 3 hours
  4. 2.4 hours Correct answer.

Explanation

In one hour the pipes fill 1/6 + 1/4 = 5/12 of the tank. The time to fill the tank is the reciprocal of this rate, 12/5 = 2.4 hours.

Question 20Mathematics

A vessel contains 40 litres of a milk-water mixture in the ratio 3 : 1. How much water must be added so that the ratio of milk to water becomes 3 : 2?

  1. 8 litres
  2. 12 litres
  3. 10 litres Correct answer.
  4. 5 litres

Explanation

Initially milk = 3/4 × 40 = 30 litres and water = 10 litres. Adding water changes only the water, so we need 30 : (10 + w) = 3 : 2, giving 60 = 30 + 3w and w = 10 litres.

Question 21Mathematics

Two numbers are in the ratio 5 : 7 and their HCF is 6. Find their LCM.

  1. 105
  2. 630
  3. 42
  4. 210 Correct answer.

Explanation

When two numbers are in the ratio a : b and their HCF is h, the numbers are ah and bh, here 30 and 42. Since HCF × LCM = product of the numbers, LCM = (30 × 42)/6 = 210.

Question 22Mathematics

Two successive discounts of 20% and 10% are given on an article. What single discount is equivalent to them?

  1. 32%
  2. 30%
  3. 25%
  4. 28% Correct answer.

Explanation

After a 20% discount the price is 80% of the marked price, and after a further 10% discount it is 90% of that, i.e. 0.8 × 0.9 = 0.72 of the marked price. The equivalent single discount is therefore 100% − 72% = 28%.

Question 23Mathematics

Two trains of lengths 120 m and 180 m are running in opposite directions at 40 km/h and 32 km/h. How long will they take to cross each other completely?

  1. 12 seconds
  2. 15 seconds Correct answer.
  3. 20 seconds
  4. 18 seconds

Explanation

In opposite directions the relative speed is 40 + 32 = 72 km/h = 72 × 5/18 = 20 m/s. The distance to be covered is the combined length 120 + 180 = 300 m, so the time is 300 ÷ 20 = 15 seconds.

Question 24Mathematics

A shopkeeper marks an article 40% above its cost price and then allows a discount of 25% on the marked price. What is his result?

  1. 5% profit Correct answer.
  2. no profit no loss
  3. 10% profit
  4. 5% loss

Explanation

Let the cost price be 100, so the marked price is 140. After a 25% discount the selling price is 140 × 0.75 = 105, which is 5 more than the cost price. Hence there is a profit of 5%.

Question 25Mathematics

Find the volume of a cylinder whose radius is 7 cm and whose height is 10 cm. (Take π = 22/7)

  1. 1540 cm³ Correct answer.
  2. 154 cm³
  3. 2200 cm³
  4. 1440 cm³

Explanation

The volume of a cylinder is πr²h. Substituting, volume = (22/7) × 7 × 7 × 10 = 22 × 7 × 10 = 1540 cm³.

Question 26Mathematics

Simplify: 16 + 4 × 5 − 18 ÷ 3

  1. 24
  2. 42
  3. 94
  4. 30 Correct answer.

Explanation

Under BODMAS, division and multiplication are carried out before addition and subtraction: 18 ÷ 3 = 6 and 4 × 5 = 20, so the expression becomes 16 + 20 − 6 = 30.

Question 27Mathematics

Find the HCF of 36, 60 and 84.

  1. 24
  2. 6
  3. 12 Correct answer.
  4. 4

Explanation

Writing each number in prime factor form: 36 = 2² × 3², 60 = 2² × 3 × 5 and 84 = 2² × 3 × 7. The highest common factor is therefore 2² × 3 = 12.

Question 28Mathematics

The cube root of 3375 is:

  1. 45
  2. 15 Correct answer.
  3. 35
  4. 25

Explanation

Since 15 × 15 × 15 = 3375, the cube root of 3375 equals 15.

Question 29Mathematics

What is the average of the first ten natural numbers?

  1. 5
  2. 5.5 Correct answer.
  3. 6
  4. 55

Explanation

The first ten natural numbers are 1 to 10, whose sum is (10 × 11)/2 = 55. The average is 55 ÷ 10 = 5.5.

Question 30Mathematics

Find the simple interest on ₹4,500 at 8% per annum for 3 years.

  1. ₹1,080 Correct answer.
  2. ₹360
  3. ₹5,580
  4. ₹3,240

Explanation

Simple interest = (P × R × T)/100 = (4500 × 8 × 3)/100 = ₹1,080.

Question 31Mathematics

Which of the following numbers is exactly divisible by 9?

  1. 5123
  2. 4527 Correct answer.
  3. 2734
  4. 3421

Explanation

A number is divisible by 9 when the sum of its digits is a multiple of 9. For 4527 the digit sum is 4 + 5 + 2 + 7 = 18, which is divisible by 9.

Question 32Mathematics

If x/4 = 7, what is the value of x + 5?

  1. 28
  2. 12
  3. 33 Correct answer.
  4. 23

Explanation

Multiplying both sides of x/4 = 7 by 4 gives x = 28. Therefore x + 5 = 28 + 5 = 33.

Question 33Mathematics

Find the next term of the series: 2, 6, 12, 20, 30, ?

  1. 40
  2. 42 Correct answer.
  3. 44
  4. 36

Explanation

The differences between consecutive terms are 4, 6, 8 and 10. The next difference should be 12, so the next term is 30 + 12 = 42.

Question 34Mathematics

A number is first increased by 20% and then decreased by 20%. What is the net change?

  1. 4% increase
  2. No change
  3. 4% decrease Correct answer.
  4. 2% decrease

Explanation

Taking the number as 100, a 20% increase gives 120, and a 20% decrease on 120 gives 96. Since 96 is 4 less than 100, the net result is a 4% decrease.

Question 35Mathematics

By selling an article for ₹720, a shopkeeper loses 10%. What is the cost price of the article?

  1. ₹792
  2. ₹720
  3. ₹648
  4. ₹800 Correct answer.

Explanation

Selling price = cost price × (100 − loss%)/100, so 720 = CP × 90/100, giving CP = 720 × 100/90 = ₹800.

Question 36Mathematics

₹1,200 is divided among A, B and C in the ratio 2 : 3 : 5. How much does B get?

  1. ₹240
  2. ₹600
  3. ₹300
  4. ₹360 Correct answer.

Explanation

The total number of parts is 2 + 3 + 5 = 10, so one part is ₹1,200 ÷ 10 = ₹120. B's share is 3 parts, that is 3 × 120 = ₹360.

Question 37Mathematics

15 men can complete a piece of work in 20 days. How many men are needed to complete it in 12 days?

  1. 18
  2. 24
  3. 30
  4. 25 Correct answer.

Explanation

The work requires 15 × 20 = 300 man-days. To finish it in 12 days the number of men needed is 300 ÷ 12 = 25.

Question 38Mathematics

The average of five numbers is 27. If one number, 35, is removed, what is the average of the remaining four numbers?

  1. 26
  2. 23
  3. 25 Correct answer.
  4. 24

Explanation

The sum of the five numbers is 5 × 27 = 135. Removing 35 leaves 100, and the average of the remaining four numbers is 100 ÷ 4 = 25.

Question 39Mathematics

A train 150 m long crosses a pole in 9 seconds. What is its speed in km/h?

  1. 45 km/h
  2. 60 km/h Correct answer.
  3. 54 km/h
  4. 66 km/h

Explanation

Speed = distance ÷ time = 150/9 m/s. Converting to km/h by multiplying by 18/5 gives (150/9) × (18/5) = 60 km/h.

Question 40Mathematics

A vessel contains 60 litres of a mixture of milk and water in the ratio 2 : 1. How much water must be added so that the ratio of milk to water becomes 1 : 1?

  1. 30 litres
  2. 10 litres
  3. 20 litres Correct answer.
  4. 15 litres

Explanation

The mixture contains 40 litres of milk and 20 litres of water. For a 1 : 1 ratio the water must also be 40 litres, so 40 − 20 = 20 litres of water must be added.

Question 41Mathematics

The sum of the ages of a mother and her daughter is 48 years. The mother is 24 years older than the daughter. Find the daughter's age.

  1. 12 years Correct answer.
  2. 15 years
  3. 10 years
  4. 14 years

Explanation

Let the daughter's age be x years; then the mother's age is x + 24. So x + (x + 24) = 48, giving 2x = 24 and x = 12 years.

Question 42Mathematics

Find the area of a triangle whose base is 18 cm and height is 15 cm.

  1. 135 cm² Correct answer.
  2. 150 cm²
  3. 270 cm²
  4. 90 cm²

Explanation

Area of a triangle = ½ × base × height = ½ × 18 × 15 = 135 cm².

Question 43Mathematics

A invests ₹5,000 for 12 months and B invests ₹8,000 for 6 months in a business. In what ratio should the profit be shared?

  1. 4 : 5
  2. 3 : 2
  3. 5 : 4 Correct answer.
  4. 25 : 16

Explanation

Profit shares are proportional to capital × time. For A, 5,000 × 12 = 60,000; for B, 8,000 × 6 = 48,000. The ratio is 60,000 : 48,000 = 5 : 4.

Question 44Mathematics

Three bells ring at intervals of 6, 8 and 10 minutes. If they ring together at 8 a.m., at what time will they next ring together?

  1. 9 a.m.
  2. 12 noon
  3. 10 a.m. Correct answer.
  4. 9:20 a.m.

Explanation

The bells ring together again after the LCM of 6, 8 and 10 minutes, which is 120 minutes = 2 hours. Adding 2 hours to 8 a.m. gives 10 a.m.

Question 45Mathematics

What is 3/4 of 2/5 of 200?

  1. 50
  2. 80
  3. 75
  4. 60 Correct answer.

Explanation

First find 2/5 of 200, which is 80. Then take 3/4 of 80, which is 60.

Question 46Mathematics

What is the difference between the compound interest and the simple interest on ₹10,000 for 2 years at 10% per annum?

  1. ₹100 Correct answer.
  2. ₹200
  3. ₹1,100
  4. ₹50

Explanation

SI = (10,000 × 10 × 2)/100 = ₹2,000, while CI = 10,000 × (1.1² − 1) = ₹2,100. The difference is ₹100, which for two years equals P(r/100)².

Question 47Mathematics

Pipe A fills a tank in 12 hours, pipe B in 15 hours, and pipe C empties the full tank in 20 hours. If all three are opened together, in how much time will the tank be filled?

  1. 10 hours Correct answer.
  2. 15 hours
  3. 8 hours
  4. 12 hours

Explanation

The net filling rate per hour is 1/12 + 1/15 − 1/20 = (5 + 4 − 3)/60 = 6/60 = 1/10. The tank therefore fills in 10 hours.

Question 48Mathematics

A car covers the first 60 km at 30 km/h and the next 60 km at 60 km/h. What is its average speed for the whole journey?

  1. 45 km/h
  2. 40 km/h Correct answer.
  3. 42 km/h
  4. 48 km/h

Explanation

The car takes 2 hours for the first 60 km and 1 hour for the next 60 km, so total time is 3 hours for 120 km. Average speed = 120 ÷ 3 = 40 km/h; the simple mean of the two speeds is not valid because the times differ.

Question 49Mathematics

Find the volume of a sphere of radius 3 cm, in terms of π.

  1. 36π cm³ Correct answer.
  2. 12π cm³
  3. 108π cm³
  4. 27π cm³

Explanation

Volume of a sphere = (4/3)πr³ = (4/3) × π × 27 = 36π cm³.

Question 50Mathematics

A sum of money becomes 4 times itself in 10 years at simple interest. In how many years will it become 7 times itself at the same rate?

  1. 25 years
  2. 20 years Correct answer.
  3. 30 years
  4. 15 years

Explanation

Becoming 4 times in 10 years means the interest equals 3 times the principal in 10 years, so one principal's worth of interest takes 10/3 years. To become 7 times, the interest must be 6 times the principal, taking 6 × 10/3 = 20 years.