Mathematics questions and answers

Mathematics Questions and Answers

How good are you with figures and formulas? Find out with these Mathematics past questions and answers. This Test is useful for both job aptitude test candidates and students preparing for JAMB, WAEC, NECO or Post UTME.

486.

If 2\(^{x + y}\) = 16 and 4\(^{x - y} = \frac{1}{32}\), find the values of x and y

A.

x = \(\frac{3}{4}\), y = \(\frac{11}{4}\)

B.

x = \(\frac{3}{4}\), y = \(\frac{13}{4}\)

C.

x = \(\frac{2}{3}\), y = \(\frac{4}{5}\)

D.

x = \(\frac{2}{3}\), y = \(\frac{13}{4}\)

Correct answer is B

2\(^{x + y}\) = 16 ; 4\(^{x - y}\) = \(\frac{1}{32}\).

\(\implies 2^{x + y} = 2^4\)

\(x + y = 4 ... (1)\)

\(2^{2(x - y)} = 2^{-5} \)

\(2^{2x - 2y} = 2^{-5}\)

\(\implies 2x - 2y = -5 ... (2)\)

Solving the equations (1) and (2) simultaneously, we have

x = \(\frac{3}{4}\) and y = \(\frac{13}{4}\)

487.

Evaluate \((\frac{6}{0.32} \div \frac{2}{0.084})^{-1}\) correct to 1 decimal place.

A.

1.3

B.

2.5

C.

4.6

D.

3.2

Correct answer is A

\((\frac{6}{0.32} \div \frac{2}{0.084})^{-1}\)

= \((\frac{600}{32} \div \frac{2000}{84})^{-1}\)

= \((\frac{600}{32} \times \frac{84}{2000})^{-1}\)

= \((\frac{63}{80})^{-1}\)

= \(\frac{80}{63}\)

= 1.3 (to 1 decimal place)

488.

The weight of a day-old chick was measured to be 0.21g. If the actual weight of the chick is 0.18g, what was the percentage error in the measurement?

A.

15.5%

B.

18.2%

C.

14.8%

D.

16.7%

Correct answer is D

Actual weight = 0.18g

Error = 0.21g - 0.18g

= 0.03g

% error = \(\frac{0.03}{0.18} \times 100%\)

= 16.7%

489.

The angles of a polygon are given by 2x, 5x, x and 4x respectively. The value of x is

A.

31°

B.

30°

C.

26°

D.

48°

Correct answer is B

Since there are 4 angles given, the polygon is a quadrilateral.

Sum of angle in a quadrilateral = 360°

∴∴ 2x + 5x + x + 4x = 360°

12x = 360°

x = 30°

490.

If S = (4t + 3)(t - 2), find ds/dt when t = 5 secs.

A.

50 units per sec

B.

35 units per sec

C.

22 units per sec

D.

13 units per sec

Correct answer is B

\(s = (4t + 3)(t - 2)\)

\(\frac{\mathrm d s}{\mathrm d t} = (4t + 3)(1) + (t - 2)(4)\)

= \(4t + 3 + 4t - 8\)

= 8t - 5

\(\frac{\mathrm d s}{\mathrm d t} (t = 5 secs) = 8(5) - 5\)

= 40 - 5 

= 35 units per sec