In an arithmetic progression the 5th term is 14 and the 9th term is 26. What is the common difference?
- 6
- 2
- 4
- 3 Correct answer.
Explanation
For an AP, a9 − a5 = (9 − 5)d, so 26 − 14 = 4d, giving d = 3. The first term is then a = 14 − 4(3) = 2.
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For an AP, a9 − a5 = (9 − 5)d, so 26 − 14 = 4d, giving d = 3. The first term is then a = 14 − 4(3) = 2.
Here a = 3 and d = 4, so a20 = 3 + 19(4) = 79. The sum is S20 = (20/2)(3 + 79) = 10 × 82 = 820.
Dividing a6 by a3 gives r³ = 96/12 = 8, so r = 2. The first term is then 12/2² = 3.
This is a GP with first term a = 1 and ratio r = 1/3, and |r| < 1. The infinite sum is a/(1 − r) = 1/(1 − 1/3) = 3/2.
Equal roots require the discriminant b² − 4ac to vanish: 49 − 4k = 0, so k = 49/4.
Sum of roots = 4 and product = 4 − 3 = 1. The equation is x² − (sum)x + product = 0, that is x² − 4x + 1 = 0.
Using the distance formula, √[(3+1)² + (−2−1)²] = √(16 + 9) = √25 = 5.
Slope = (13 − 5)/(6 − 2) = 8/4 = 2. Rise over run is computed from differences in y over differences in x.
The given line has slope −2/3, so a perpendicular line has slope 3/2. Through the origin this is y = (3/2)x, i.e. 3x − 2y = 0.
The expression matches sin(A + B) with A = 30° and B = 60°, so it equals sin 90° = 1.
With opposite 3 and adjacent 4, the hypotenuse is 5. In the first quadrant sin θ = opposite/hypotenuse = 3/5.
Since 65° = 90° − 25°, we have sin 65° = cos 25°. Then sin²25° + cos²25° = 1 by the Pythagorean identity.
The height is opposite the 60° angle, so height = 10 sin 60° = 10 × (√3/2) = 5√3 m.
The sum is 40 and there are 5 observations, so the mean is 40/5 = 8.
Arranged in order: 3, 5, 7, 9, 11, 13. With an even count, the median is the average of the two middle values (7 + 9)/2 = 8.
P(first red) = 5/12 and P(second red | first red) = 4/11. Their product is 20/132 = 5/33.
Favourable outcomes are (3,6), (4,5), (5,4), (6,3), giving 4 outcomes. So the probability is 4/36 = 1/9.
The total surface area of a sphere is 4πr² = 4 × (22/7) × 49 = 616 cm².
Slant height l = √(r² + h²) = √(9 + 16) = 5 cm. Curved surface area = πrl = π × 3 × 5 = 15π cm².
Side = ∛512 = 8 cm. Total surface area = 6a² = 6 × 64 = 384 cm².
Using Euclid's algorithm, 126 = 84 × 1 + 42 and 84 = 42 × 2 + 0, so HCF = 42. Prime factorisation gives 2² × 3 × 7 for 84 and 2 × 3² × 7 for 126, whose common part is 42.
The LCM of 12, 15 and 18 is 180. The required number is LCM + 5 = 185, since the remainder 5 must be added to a common multiple.
Since 32 = 2⁵, log₂ 32 = 5; since 27 = 3³, log₃ 27 = 3. Their sum is 8.
log₁₀(2³⁰) = 30 × 0.3010 = 9.03. A number with characteristic 9 has 9 + 1 = 10 digits.
Here α + β = 5/2 and αβ = 3/2. Then α² + β² = (α + β)² − 2αβ = 25/4 − 3 = 13/4.
The intersection A ∩ B collects elements present in both sets, namely 3 and 4. Counting them gives exactly 2 elements, while the union A ∪ B would have 6 elements.
Here the first term a = 3 and the common difference d = 4. The nth term is a + (n − 1)d, so the 10th term is 3 + 9 × 4 = 39.
With a = 5, d = 4 and n = 20, the sum is (n/2)[2a + (n − 1)d] = 10 × (10 + 76) = 10 × 84 = 840. The 20th term is 5 + 19 × 4 = 81, and the average of first and last terms times 20 also gives 840.
The first term is 2 and each term is multiplied by the common ratio 3. Continuing the pattern gives 2, 6, 18, 54, so the 4th term is 54, which also equals 2 × 3³.
Using the section formula with ratio m : n = 1 : 2, the x-coordinate is (1×7 + 2×1)/3 = 3 and the y-coordinate is (1×8 + 2×2)/3 = 4. So the point is (3, 4).
The two legs along the axes have lengths 4 and 3, and they meet at a right angle at the origin. The area of a right triangle is half the product of the legs, so it is ½ × 4 × 3 = 6 square units.
Setting y = 0 gives P = (4, 0), and setting x = 0 gives Q = (0, 3). The distance PQ is √(16 + 9) = √25 = 5.
Equal roots require the discriminant b² − 4ac to vanish. Here 36 − 4k = 0, giving k = 9, and the equation then becomes (x − 3)² = 0.
A quadratic with sum S and product P of zeroes is x² − Sx + P. Substituting S = −3 and P = −10 gives x² + 3x − 10, whose zeroes are 2 and −5.
By the remainder theorem, the remainder on dividing by x − 2 is p(2). Computing 8 − 16 + 2 + 6 gives 0, so x − 2 is a factor of the polynomial.
Since 1 + tan² θ = sec² θ, the expression becomes sec² θ × cos² θ. Because sec θ = 1/cos θ, this product simplifies to exactly 1 for every θ where the functions are defined.
The identity cosec² θ − cot² θ = 1 factors as (cosec θ − cot θ)(cosec θ + cot θ) = 1. Dividing 1 by the given value 1/2 gives cosec θ + cot θ = 2.
In the right triangle formed, tan 45° equals the height divided by the horizontal distance. Since tan 45° = 1, the height equals the distance, namely 30 m.
The standard values are cos 0° = 1, sin 90° = 1 and tan 45° = 1. Adding these three values gives 3.
The sector area is (θ/360) × πr², so it is (90/360) × (22/7) × 49 = ¼ × 154 = 38.5 cm². This is one quarter of the full circle area.
The curved surface area of a cylinder is 2πrh. Substituting gives 2 × (22/7) × 7 × 10 = 440 cm².
The volume of a sphere is (4/3)πr³, so a hemisphere has volume (2/3)πr³. With r = 3 this is (2/3) × (22/7) × 27 = 396/7 cm³.
The total of the five observations is 5 × 12 = 60. The four known observations add to 48, so the fifth is 60 − 48 = 12.
The mode is the observation occurring most frequently. The value 3 appears three times, while 5 appears twice and 7 and 9 appear once each, so the mode is 3.
There are 3 face cards (jack, queen, king) in each of the 4 suits, giving 12 face cards in total. The probability is therefore 12/52, which simplifies to 3/13.
The sample space is HH, HT, TH, TT, and three of these four outcomes contain at least one head. Hence the probability is 3/4, which is also 1 minus the probability 1/4 of getting no head.
Write 0.027 as 27/1000, whose cube root is 3/10 because 3³ = 27 and 10³ = 1000. Hence the cube root is 0.3.
Since 8 = 2³, the right side equals 2^(3x−3). Equating the exponents gives x + 1 = 3x − 3, so 2x = 4 and x = 2.
The sum of the first n odd natural numbers is n². For n = 10 this gives 100, which can be checked by adding 1 + 3 + 5 + … + 19.
The sum of the roots is k + 2 and the product is 8. Setting them equal gives k + 2 = 8, so k = 6.