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.

3,801.

Three teachers shared a packet of chalk. The first teacher got 2/5 of the chalk and the second teacher received 2/15 of the remainder. What fraction the the third teacher receive?

A.

8/15

B.

11/25

C.

12/25

D.

13/25

Correct answer is D

First teacher received \(\frac{2}{5}\) ∴Remainder \(= 1 - \frac{2}{5} = \frac{3}{5}\)
2nd teacher received; \(\frac{2}{15} of \frac{3}{5} = \frac{2}{15} \times \frac{3}{5} = \frac{2}{25}\)
3rd teacher will receive; \(1-\frac{2}{5}-\frac{2}{25}=\frac{25-10-2}{15}\\=\frac{13}{25}\)

3,802.

The length L of a simple pendulum varies directly as the square of its period T. If a pendulum with period 4 sec. is 64 cm long, find the length of pendulum whose period is 9 sec

A.

96 cm

B.

324 cm

C.

36 cm

D.

144 cm

Correct answer is B

\(L \propto T^2\)

\(L = kT^2\)

\(k = \frac{L}{T^2}\)

when T = 4, L = 64.

\(k = \frac{64}{4^2} = 4\)

\(L = 4T^2\)

when T = 9,

\(L = 4 \times 9^2 = 324cm\)

3,803.

Find the sum to infinity of the series 1/2 , 1/6, 1/18, .....

A.

2/3

B.

1/3

C.

3/4

D.

1

Correct answer is C

\(a=\frac{1}{2}\\r=\frac{\frac{1}{6}}{\frac{1}{2}}=\frac{1}{6}\times\frac{2}{1}=\frac{1}{3}\\S_\infty = \frac{a}{1-r}\\S_\infty = \frac{\frac{1}{2}}{1-\frac{1}{3}}\\=\frac{\frac{1}{2}}{\frac{3}{2}}\\=\frac{1}{2}\times\frac{3}{2}\\=\frac{3}{4}\)

3,804.

Factorize completely ac - 2bc - a + 4b2

A.

(a - 2b)(c - a - 2b)

B.

(a - 2b)(c + a +2b)

C.

(a - 2b)(c - a + 2b)

D.

(a - 2b)(c + a - 2b)

Correct answer is A

ac - 2bc - a2 + 4b2
ac - 2bc - (a2 - 4b2)
ac - 2bc - (a2 -(2b)2)
c(a - 2b) - {(a - 2b)(a + 2b)}
(a - 2b)(c - (a + 2b))
(a - 2b)(c - a - 2b)

3,805.

The nth term of two sequences are Qn = 3 . 2n - 2 and Um = 3 . 22m - 3. Find the product of Q2 and U2.

A.

18

B.

12

C.

6

D.

3

Correct answer is A

Qn = 3 * 2n - 2
Um = 3 * 22m - 3
Q2 * U2 = (3 * 22 - 2) * (3 * 22(2) - 3)
= 3 * 20 * 3 * 21
= 3 * 1 * 3 * 2
= 18