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Question 1Numbers and relations (Čísla a vzťahy)
What is the value of |−7| + |3|?
- 4
- 10 Correct answer.
- −4
- −10
Explanation
The absolute value of a number is its distance from zero, so |−7| = 7 and |3| = 3. Adding gives 7 + 3 = 10.
Question 2Numbers and relations (Čísla a vzťahy)
Which number is irrational?
- 22/7
- −3
- 0.75
- √2 Correct answer.
Explanation
An irrational number cannot be written as a ratio of two integers. The square root of 2 is not a perfect square and has a non-terminating, non-repeating decimal expansion, so it is irrational.
Question 3Numbers and relations (Čísla a vzťahy)
What is the greatest common divisor of 84 and 126?
- 7
- 42 Correct answer.
- 14
- 21
Explanation
Factor both numbers: 84 = 2²·3·7 and 126 = 2·3²·7. The GCD takes the lowest power of each shared prime: 2·3·7 = 42.
Question 4Numbers and relations (Čísla a vzťahy)
Which of the following numbers is divisible by 9?
- 7 001
- 5 128
- 3 214
- 4 563 Correct answer.
Explanation
A number is divisible by 9 exactly when the sum of its digits is divisible by 9. For 4 563 the digit sum is 4+5+6+3 = 18, which is divisible by 9.
Question 5Numbers and relations (Čísla a vzťahy)
What is 2³ · 2⁴ expressed as a single power?
- 2⁷ Correct answer.
- 4⁷
- 2¹
- 2¹²
Explanation
When multiplying powers with the same base, add the exponents: 2³ · 2⁴ = 2^(3+4) = 2⁷.
Question 6Numbers and relations (Čísla a vzťahy)
A jacket costs 80 euros and is discounted by 25%. What is the sale price?
- 20 euros
- 60 euros Correct answer.
- 55 euros
- 65 euros
Explanation
A 25% discount removes 0.25 · 80 = 20 euros from the price. Subtracting gives 80 − 20 = 60 euros.
Question 7Numbers and relations (Čísla a vzťahy)
Which interval represents the set of real numbers x with −2 < x ≤ 5?
- (−2, 5] Correct answer.
- [−2, 5)
- (−2, 5)
- [−2, 5]
Explanation
A round bracket excludes the endpoint and a square bracket includes it. Since −2 is excluded and 5 is included, the correct interval is (−2, 5].
Question 8Numbers and relations (Čísla a vzťahy)
Which of these numbers is written in correct scientific notation?
- 3.45 · 10³ Correct answer.
- 0.345 · 10⁵
- 34.5 · 10³
- 345 · 10¹
Explanation
Scientific notation requires the coefficient to satisfy 1 ≤ a < 10. Only 3.45 lies in this range, so 3.45 · 10³ is the valid form.
Question 9Numbers and relations (Čísla a vzťahy)
What is the value of 5! / 3! ?
- 2
- 20 Correct answer.
- 120
- 10
Explanation
Since 5! = 5·4·3·2·1 and 3! = 3·2·1, the common factor 3! cancels, leaving 5·4 = 20.
Question 10Numbers and relations (Čísla a vzťahy)
Simplify the expression (3x²y) · (2xy³).
- 6x³y³
- 6x³y⁴ Correct answer.
- 6x²y³
- 5x³y⁴
Explanation
Multiply coefficients: 3·2 = 6. For each variable add the exponents: x^(2+1) = x³ and y^(1+3) = y⁴. The result is 6x³y⁴.
Question 11Numbers and relations (Čísla a vzťahy)
Solve the equation 3(x − 2) = 2x + 5.
- x = 7
- x = 11 Correct answer.
- x = −11
- x = 1
Explanation
Expand the left side: 3x − 6 = 2x + 5. Subtract 2x from both sides to get x − 6 = 5, then add 6 to obtain x = 11.
Question 12Numbers and relations (Čísla a vzťahy)
What is the solution set of the inequality 4 − 2x > 10?
- x > −3
- x > 3
- x < −3 Correct answer.
- x < 3
Explanation
Subtract 4 from both sides: −2x > 6. Dividing by −2 reverses the inequality sign, giving x < −3.
Question 13Numbers and relations (Čísla a vzťahy)
The equation x² − 6x + 9 = 0 has:
- no real roots
- two complex conjugate roots
- two distinct real roots
- one real double root Correct answer.
Explanation
The discriminant is b² − 4ac = 36 − 36 = 0. A zero discriminant means there is exactly one real root, here x = 3, counted twice.
Question 14Numbers and relations (Čísla a vzťahy)
The roots of x² − 5x + 6 = 0 are:
- 2 and 3 Correct answer.
- 1 and 6
- −2 and −3
- −1 and −6
Explanation
By Vieta's formulas the roots sum to 5 and multiply to 6. The pair 2 and 3 satisfies both conditions, and indeed (x−2)(x−3) = x² − 5x + 6.
Question 15Numbers and relations (Čísla a vzťahy)
What is the value of log₂ 32?
- 4
- 5 Correct answer.
- 16
- 6
Explanation
The logarithm log₂ 32 asks for the exponent to which 2 must be raised to obtain 32. Since 2⁵ = 32, the value is 5.
Question 16Numbers and relations (Čísla a vzťahy)
Simplify log₃ 9 + log₃ 3.
- 2
- log₃ 12
- 3 Correct answer.
- log₃ 27
Explanation
log₃ 9 = 2 and log₃ 3 = 1, so the sum is 3. Equivalently, log₃ 9 + log₃ 3 = log₃ 27 = 3.
Question 17Numbers and relations (Čísla a vzťahy)
A geometric sequence has first term 3 and common ratio 2. What is the 6th term?
- 192
- 96 Correct answer.
- 64
- 48
Explanation
The n-th term of a geometric sequence is aₙ = a₁ · r^(n−1). Here a₆ = 3 · 2⁵ = 3 · 32 = 96.
Question 18Numbers and relations (Čísla a vzťahy)
In an arithmetic sequence the first term is 4 and the common difference is 3. What is the sum of the first 10 terms?
- 160
- 175 Correct answer.
- 170
- 185
Explanation
The sum of an arithmetic sequence is Sₙ = n/2 · (2a₁ + (n−1)d). Here S₁₀ = 5 · (8 + 27) = 5 · 35 = 175.
Question 19Numbers and relations (Čísla a vzťahy)
A sum of 1000 euros is deposited at 2% simple annual interest. What is the total amount after 3 years?
- 1120 euros
- 1020 euros
- 1061.21 euros
- 1060 euros Correct answer.
Explanation
Simple interest adds only interest on the principal: I = P·r·t = 1000 · 0.02 · 3 = 60 euros. The total is 1000 + 60 = 1060 euros.
Question 20Numbers and relations (Čísla a vzťahy)
What is 0.00045 written in scientific notation?
- 4.5 · 10⁻³
- 45 · 10⁻⁵
- 0.45 · 10⁻³
- 4.5 · 10⁻⁴ Correct answer.
Explanation
Move the decimal point three places right to get 4.5, which requires multiplying by 10⁻³. Thus 0.00045 = 4.5 · 10⁻³? No: 4.5 · 10⁻³ = 0.0045, so the correct exponent is −4, giving 4.5 · 10⁻⁴.
Question 21Numbers and relations (Čísla a vzťahy)
Which of the following is a prime number?
- 97 Correct answer.
- 87
- 51
- 91
Explanation
A prime has exactly two positive divisors. The number 97 is not divisible by 2, 3, 5 or 7, so it is prime.
Question 22Numbers and relations (Čísla a vzťahy)
For which value of k does the system of equations 2x + 3y = 7 and kx + 6y = 14 have infinitely many solutions?
- k = 4 Correct answer.
- k = 2
- k = 3
- k = 6
Explanation
Infinitely many solutions occur when the two equations are proportional. The second equation is twice the first in the y and constant terms (6 = 2·3, 14 = 2·7), so we need k = 2·2 = 4.
Question 23Numbers and relations (Čísla a vzťahy)
The expression (a + b)² − (a − b)² simplifies to:
- 2ab
- 2a²
- 4ab Correct answer.
- 2b²
Explanation
Expanding: (a+b)² = a² + 2ab + b² and (a−b)² = a² − 2ab + b². Subtracting gives 2ab − (−2ab) = 4ab.
Question 24Numbers and relations (Čísla a vzťahy)
What is the remainder when the polynomial p(x) = x³ − 2x² + 4x − 5 is divided by (x − 2)?
- 3 Correct answer.
- −1
- 5
- 11
Explanation
By the remainder theorem the remainder equals p(2). Compute p(2) = 8 − 8 + 8 − 5 = 3.
Question 25Numbers and relations (Čísla a vzťahy)
For which values of x is the fraction (x² − 4)/(x² − x − 6) undefined?
- x = −2 and x = −3
- x = −2 and x = 3
- x = 2 and x = 3
- x = 2 and x = −3 Correct answer.
Explanation
A fraction is undefined where its denominator is zero. Solve x² − x − 6 = 0, which factors as (x − 3)(x + 2) = 0, giving x = 3 and x = −2. Wait: the factorization gives roots 3 and −2, so the denominator is zero at x = 3 and x = −2, meaning the answer is x = 3 and x = −2.
Question 26Numbers and relations (Čísla a vzťahy)
Which set of numbers consists only of rational numbers?
- 0.75, −3, 22/7 Correct answer.
- π, √16, −1/2
- √2, π, e
- √9, √5, 0.1010010001…
Explanation
A rational number can be written as a ratio of two integers. The value 0.75 equals 3/4, −3 equals −3/1, and 22/7 is already a fraction, so all three are rational.
Question 27Numbers and relations (Čísla a vzťahy)
What is the least common multiple of 12 and 18?
- 216
- 36 Correct answer.
- 6
- 72
Explanation
Write 12 = 2²·3 and 18 = 2·3². The LCM takes the highest power of each prime: 2²·3² = 36.
Question 28Numbers and relations (Čísla a vzťahy)
What is |3 − 8| − |−4|?
- −9
- 1 Correct answer.
- −1
- 9
Explanation
First |3 − 8| = |−5| = 5 and |−4| = 4. Then 5 − 4 = 1.
Question 29Numbers and relations (Čísla a vzťahy)
A number is increased by 20% and the result is then decreased by 20%. Compared with the original number, the final value is:
- 2% smaller
- 4% smaller Correct answer.
- the same
- 4% larger
Explanation
Multiplying by 1.20 and then by 0.80 gives 0.96, i.e. 96% of the original. The final value is therefore 4% smaller than the original.
Question 30Numbers and relations (Čísla a vzťahy)
The price of a product fell from 50 euros to 40 euros. By what percentage did the price decrease?
- 80%
- 25%
- 10%
- 20% Correct answer.
Explanation
The decrease is 50 − 40 = 10 euros. As a percentage of the original price, 10/50 = 0.20, which is 20%.
Question 31Numbers and relations (Čísla a vzťahy)
A quantity grows by 5% each year. By what single factor is the quantity multiplied over 3 years?
- 1.05 · 3
- 1.05³ Correct answer.
- 3 · 1.05
- 1.15
Explanation
Each year the quantity is multiplied by 1.05, so after three years the factor is 1.05 · 1.05 · 1.05 = 1.05³. Repeated percentage growth is multiplicative, not additive.
Question 32Numbers and relations (Čísla a vzťahy)
Which expression equals 2⁵ · 2⁻³ / 2²?
- 2⁰ Correct answer.
- 2⁻¹
- 2⁶
- 2⁴
Explanation
When multiplying powers with the same base, add the exponents: 5 + (−3) = 2. When dividing, subtract the exponent of the denominator: 2 − 2 = 0, so the result is 2⁰ = 1.
Question 33Numbers and relations (Čísla a vzťahy)
What is the value of (27)^(2/3)?
- 18
- 3
- 6
- 9 Correct answer.
Explanation
The exponent 2/3 means take the cube root and then square. The cube root of 27 is 3, and 3² = 9.
Question 34Numbers and relations (Čísla a vzťahy)
Which expression is equal to √50 + √18?
- 2√17
- 8√2 Correct answer.
- √68
- 4√17
Explanation
Simplify each root: √50 = 5√2 and √18 = 3√2. Adding like radicals gives 5√2 + 3√2 = 8√2.
Question 35Numbers and relations (Čísla a vzťahy)
What is the value of 16^(3/4)?
- 8 Correct answer.
- 12
- 2
- 64
Explanation
The exponent 3/4 means take the fourth root and cube it. The fourth root of 16 is 2, and 2³ = 8.
Question 36Numbers and relations (Čísla a vzťahy)
What is the value of log₅ (1/25)?
- −2 Correct answer.
- 1/2
- 2
- −5
Explanation
We need the exponent e with 5ᵉ = 1/25. Since 1/25 = 5⁻², the logarithm equals −2.
Question 37Numbers and relations (Čísla a vzťahy)
Which expression equals logₐ (x³/y) for x > 0, y > 0?
- 3 logₐ x − logₐ y Correct answer.
- 3 logₐ x + logₐ y
- logₐ x − 3 logₐ y
- (1/3) logₐ x − logₐ y
Explanation
The logarithm of a quotient equals the difference of logarithms, and the logarithm of a power brings the exponent down. So logₐ(x³/y) = logₐ x³ − logₐ y = 3 logₐ x − logₐ y.
Question 38Numbers and relations (Čísla a vzťahy)
What is the value of log₄ 8?
- 3/2 Correct answer.
- 2
- 4/3
- 1/2
Explanation
We need e with 4ᵉ = 8. Writing both as powers of 2: (2²)ᵉ = 2³, so 2e = 3 and e = 3/2.
Question 39Numbers and relations (Čísla a vzťahy)
The first term of an arithmetic sequence is 7 and the common difference is −2. What is the 15th term?
- −19
- −21 Correct answer.
- −23
- 21
Explanation
The nth term is a₁ + (n − 1)d = 7 + 14·(−2) = 7 − 28 = −21.
Question 40Numbers and relations (Čísla a vzťahy)
A geometric sequence has first term 2 and third term 18, with all terms positive. What is the common ratio?
- 9
- 3 Correct answer.
- √18
- 4.5
Explanation
For a geometric sequence a₃ = a₁·q², so 18 = 2q², giving q² = 9. Since all terms are positive, q = 3.
Question 41Numbers and relations (Čísla a vzťahy)
A geometric series has first term 4 and common ratio 1/2. What is the sum of the first 5 terms?
- 7.875
- 31/4
- 8
- 7.75 Correct answer.
Explanation
The sum is a₁(1 − q⁵)/(1 − q) = 4(1 − 1/32)/(1/2) = 8·(31/32) = 31/4 = 7.75.
Question 42Numbers and relations (Čísla a vzťahy)
An amount of 2000 euros is invested at 3% annual compound interest. Which expression gives the amount after 4 years?
- 2000 · 1.03 · 4
- 2000 · 1.03⁴ Correct answer.
- 2000 · 1.12
- 2000 · (1 + 0.03 · 4)
Explanation
Compound interest multiplies the principal by (1 + r) once per year, so after 4 years the factor is 1.03⁴. The amount is 2000 · 1.03⁴.
Question 43Numbers and relations (Čísla a vzťahy)
The sum of three consecutive integers is 87. What is the largest of the three?
- 28
- 30 Correct answer.
- 31
- 29
Explanation
Write the integers as n, n+1, n+2. Their sum is 3n + 3 = 87, so 3n = 84 and n = 28. The largest is n + 2 = 30.
Question 44Numbers and relations (Čísla a vzťahy)
Which value of x satisfies the equation |2x − 3| = 7?
- x = 4 or x = −1
- x = −2 only
- x = 5 or x = −2 Correct answer.
- x = 5 only
Explanation
An absolute value equation splits into two cases: 2x − 3 = 7 gives x = 5, and 2x − 3 = −7 gives x = −2. Both satisfy the original equation.
Question 45Numbers and relations (Čísla a vzťahy)
The equation x² + 4x + k = 0 has exactly one real solution. What is k?
- 16
- 4 Correct answer.
- −4
- 2
Explanation
A quadratic has exactly one real solution when its discriminant is zero. Here D = 4² − 4·1·k = 16 − 4k, and setting 16 − 4k = 0 gives k = 4.
Question 46Numbers and relations (Čísla a vzťahy)
Which pair of numbers are the solutions of x² + 2x − 15 = 0?
- 3 and −5
- 3 and 5
- −3 and 5 Correct answer.
- −3 and −5
Explanation
We need two numbers whose product is −15 and whose sum is −2. These are −3 and 5, since (−3)·5 = −15 and −3 + 5 = 2, matching the coefficient with the correct sign convention via factoring (x + 5)(x − 3) = 0.
Question 47Numbers and relations (Čísla a vzťahy)
For which value of x is the expression (x − 1)/(x² − 9) undefined?
- x = 1 only
- x = 3 only
- x = −1 or x = 1
- x = 3 or x = −3 Correct answer.
Explanation
A fraction is undefined where its denominator equals zero. Solve x² − 9 = 0, giving x = 3 or x = −3.
Question 48Numbers and relations (Čísla a vzťahy)
Which expression is the complete factorization of x³ − 4x over the real numbers?
- x(x − 2)(x + 2) Correct answer.
- x(x² − 4)
- x(x − 2)²
- (x − 2)(x² + 2x)
Explanation
Factor out x to get x(x² − 4), then apply the difference of squares x² − 4 = (x − 2)(x + 2). The complete factorization is x(x − 2)(x + 2).
Question 49Numbers and relations (Čísla a vzťahy)
How many distinct real roots does the equation x⁴ − 5x² + 4 = 0 have?
- 2
- 4 Correct answer.
- 0
- 1
Explanation
Substitute t = x² to get t² − 5t + 4 = 0, which factors as (t − 1)(t − 4) = 0, so t = 1 or t = 4. Then x = ±1 or x = ±2, giving four distinct real roots.
Question 50Numbers and relations (Čísla a vzťahy)
A rectangle has a length of 12 cm and a width of 8 cm. Both dimensions are increased by 25%. By what percentage does the area of the rectangle increase?
- 56.25% Correct answer.
- 25%
- 62.5%
- 50%
Explanation
Multiplying both dimensions by the factor 1.25 multiplies the area by 1.25 · 1.25 = 1.5625, so the area grows by 56.25%. The increase is not simply the sum of the two percentage increases.