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.

3,971.

If \(P344_{6} - 23P2_{6} = 2PP2_{6}\), find the value of the digit P.

A.

2

B.

3

C.

4

D.

5

Correct answer is D

Convert everything to base 10 and collect like terms, such that:

\(210P - 42P = 434 + 406\)

\(168P = 840\)

\(P = 840/168 = 5\)

3,972.

Simplify \(\frac{3(2^{n+1}) - 4(2^{n-1})}{2^{n+1} - 2^n}\)

A.

2n+1

B.

2n-1

C.

4

D.

1/4

Correct answer is C

Start by expanding \(\frac{3(2^{n+1}) - 4(2^{n-1})}{2^{n+1} - 2^n}\):

\(\frac{3 \times 2^n \times 2^1 - 2^2 \times 2^n \times 2^{-1}}{2^n \times 2 - 2^n}\)

NUMERATOR : 2\(^n\) (  3\(^1\) X 2\(^1\)  -  2\(^2\) X 2\(^-1\) )

--> 2\(^n\) ( 3 X 2 — 4 X \(\frac{1}{2}\) )

--> 2\(^n\) ( 6 - 2 ) 

--> 2\(^n\) (4)

DENOMINATOR : 2\(^n\) ( 2\(^1\)  -  1 )

--> 2\(^n\) ( 2 - 1)

  --> 2\(^n\)

 

: [ 2\(^n\) ( 4) ] ÷ 2\(^n\)

= 4

3,973.

If 314\(_10\) - 256\(_7\) = 340\(_x\), find x.

A.

7

B.

8

C.

9

D.

10

Correct answer is A

31410 - 2567 = 340x,
Convert 2567 and 340x to base 10, such that:
314 - 139 = 3x2 + 4x
=> 3x2 + 4x - 175 = 0 (quadratic)
Factorising, (x - 7) (3x + 25) = 0,
either x = 7 or x = -25/3 ( but x cannot be negative)

Therefore, x = 7.

3,974.

A man wishes to keep his money in a savings deposit at 25% compound interest so that after three years he can buy a car for N150,000. How much does he need to deposit?

A.

N112,000.50

B.

N96,000.00

C.

N85,714.28

D.

N76,800.00

Correct answer is D

Amount A = P(1+r)n;
A = N150,000, r = 25%, n = 3.
150,000 = P(1+0.25)3 = P(1.25)3

P = 150,000/1.253 =N76,800.00

3,975.

Evaluate \(\frac{(2.813 \times 10^{-3} \times 1.063)}{(5.637 \times 10^{-2})}\) reducing each number to two significant figures and leaving your answer in two significant figures.

A.

0.056

B.

0.055

C.

0.054

D.

0.54

Correct answer is B

\(\frac{2.813 \times 10^{-3} \times 1.063}{5.637 \times 10^{-2}}\)

= \(\frac{0.002813 \times 1.063}{0.05637}\)

\(\approxeq \frac{0.0028 \times 1.1}{0.056}\)

= \(0.055\)