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.

1,316.

If the sum of the roots of the equation (x - p)(2x + 1) = 0 is 1, find the value of x

A.

1\(\frac{1}{2}\)

B.

\(\frac{1}{2}\)

C.

-\(\frac{3}{2}\)

D.

-1\(\frac{1}{2}\)

Correct answer is A

(x - p)(2x + 1) = 0

2x2 + x - 2px - p = 0

2x2 + x (1 - 2p) - p = 0

2x2 - (2p - 1)x - p = 0

divide through by 2

x2 - \(\frac{(2p - 1)}{2}\)x - \(\frac{p}{2}\) = 0

compare to x2 - (sum of roots)x + product of roots = 0

sum of roots = \(\frac{2p - 1}{2}\)

But sum of roots = 1

Given; \(\frac{2p - 1}{2}\) = 1

2p - 1 = 2 x 1

2p - 1 = 2

2p = 2 + 1 = 3

p = \(\frac{3}{2}\)

p = 1\(\frac{1}{2}\)

1,317.

The subtraction below is in base seven. Find the missing number.
5 1 6 2seven
-2 6 4 4seven
--------
2 * 1 5
--------

A.

2

B.

3

C.

4

D.

5

Correct answer is A

5 1 6 2seven
-2 6 4 4seven
--------
2 2 1 5
--------

the missing number is 2

1,318.

What is the value of x when y = 5?

y = \(\frac{1}{2}\)  x + 1

A.

8

B.

9

C.

10

D.

11

Correct answer is A

when y = 5; x = ?; y = \(\frac{1}{2}\)x + 1

5 = \(\frac{1}{2}\)x + 1

5 - 1 = \(\frac{1}{2}\)x

4 = \(\frac{1}{2}\)x

x = 4 x 2

x = 8

1,319.

\(\begin{array}{c|c} x & 0 & 2 & 4 & 6\\ \hline y & 1 & 2 & 3 & 4\end{array}\).
The table is for the relation y = mx + c where m and c are constants. What is the equation of the line described in the tablet?

A.

y = 2x

B.

y = x + 1

C.

y = x

D.

y = \(\frac{1}{2}x + 1\)

Correct answer is D

y = mx + c; when x = 0; y = 1

1 = m(0) + c; 1 = 0 + c; c = 1

when x = 2; y = 2

2 = m(2) + c; 2 = 2m + c; but c = 1

2 = 2m + 1

2 - 1 = 2m

2m = 1

m = \(\frac{1}{2}\)

y = \(\frac{1}{2}\)x + 1

1,320.

The mean age of R men in a club is 50 years, Two men aged 55 and 63, left the club and the mean age reduced by 1 year. Find the value of R

A.

18

B.

20

C.

22

D.

28

Correct answer is B

mean age = \(\frac{\text{sum of ages}}{\text{no. of men}}\)

50 = \9\frac{sum}{R}\)

sum = 50R.....(1)

Sum of ages of the men that left = 55 + 63 = 188

remaining sum = 50R - 118

remaining no. of men = R - 2

now mean age = 50 - 1 = 49 years

49 = \(\frac{50R - 118}{R - 2}\)

49(R - 2) = 50R - 118

49R - 50R = -188 - 98

-R = -20

R = 20