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.

261.

Solve: 2\(^{√2x + 1}\) = 32

A.

13

B.

24

C.

12

D.

11

Correct answer is C

2\(^{√2x + 1}\) = 32

2\(^{√2x + 1}\) = 2\(^5\)

√2x + 1 = 5

square both sides

2x + 1 = 5\(^2\)

2x + 1 = 25

2x = 25 - 1

2x = 24

x = \(\frac{24}{2}\)

x = 12

262.

Simplify: (11\(_{two}\))\(^2\)

A.

1001\(_2\)

B.

1101\(_2\)

C.

101\(_2\)

D.

10001\(_2\)

Correct answer is A

(11\(_{two}\))\(^2\) = (11\(_2\) \(\times\) (11\(_2\))

= \({1 \times 2^1 + 1 \times 2^0} \times ({1 \times 2^1 + 1 \times 2^0})\)   

= \({1 \times 2 + 1 \times 1} \times ({1 \times 2 + 1 \times 1})\)

= \({2 + 1} \times ({2 + 1})\)

= 3 \(\times\) 3 

= 9\(_{10}\) or

1001\(_2\) from  

2
2 4 r1
2 2 r0
2 1 r0
  0 r1

263.

Correct 0.007985 to three significant figures.

A.

0.0109

B.

0.0800

C.

0.00799

D.

0.008

Correct answer is C

  1. To round to three significant figures, look at the fourth significant figure. It's a 5 , so round up or round down if below 5.
  2. To round to two significant figures, look at the third significant figure. It's an 8 , so round up.

264.

If (x + 2) and (x - 1) are factors of the expression \(Lx + 2kx^{2} + 24\), find the values of L and k.

A.

l = -12, k = -6

B.

l = -2 , k = 1

C.

l = -2 , k = -1

D.

l = 0, k = 1

Correct answer is A

Given (x + 2) and (x - 1), i.e. x = -2 or +1

when x = -2

L(-2) + 2k(-2)\(^2\) + 24 = 0

f(-2) = -2L + 8k = -24...(i)


And x = 1
L(1) + 2k(1) + 24 = 0


f(1):L + 2k = -24...(ii)

Subst, L = -24 - 2k in eqn (i)

-2(-24 - 2k) + 8k = -24

+48 + 4k + 8k = -24

12k = -24 - 48 = -72

k = \(frac{-72}{12}\)

k = -6

where L = -24 - 2k

L = -24 - 2(-6)

L = -24 + 12

L = -12

That is; K = -6 and L = -12

265.

A group of market women sell at least one of yam, plantain and maize. 12 of them sell maize, 10 sell yam and 14 sell plantain. 5 sell plantain and maize, 4 sell yam and maize, 2 sell yam and plantain only while 3 sell all the three items. How many women are in the group?

A.

25

B.

19

C.

18

D.

17

Correct answer is A

Let the three items be M, Y and P.
n{M ∩ Y} only = 4-3 = 1
n{M ∩ P) only = 5-3 = 2
n{ Y ∩ P} only = 2
n{M} only = 12-(1+3+2) = 6
n{Y} only = 10-(1+2+3) = 4
n{P} only = 14-(2+3+2) = 7
n{M∩P∩Y} = 3
Number of women in the group = 6+4+7+(1+2+2+3) as above =25 women.