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.

791.

Make s the subject of the relation: P = S + \(\frac{sm^2}{nr}\)

A.

s = \(\frac{mrp}{nr + m^2}\)

B.

s = \(\frac{nr + m^2}{mrp}\)

C.

s = \(\frac{nrp}{mr + m^2}\)

D.

s = \(\frac{nrp}{nr + m^2}\)

Correct answer is D

P = S + \(\frac{sm^2}{nr}\)

P = S(1 + \(\frac{m^2}{nr}\))

P = S(1 + \(\frac{nr + m^2}{nr}\))

nrp = S(nr + m2)

S = \(\frac{nrp}{nr + m^2}\)

792.

Simplify; \(\frac{2}{1 - x} - \frac{1}{x}\)

A.

\(\frac{x + 1}{x(1 - x)}\)

B.

\(\frac{3x - 1}{ x(1 - x)}\)

C.

\(\frac{3x + 1}{ x(1 - x)}\)

D.

\(\frac{x + 1}{ x(1 - x)}\)

Correct answer is D

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

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

= \(\frac{3x - 1}{x(1 - x)}\)

793.

Given that 2x + y = 7 and 3x - 2y = 3, by how much is 7x greater than 10?

A.

1

B.

3

C.

7

D.

17

Correct answer is C

2x + y = 7...(1)

3x - 2y = 3...(2)

From (1), y = 7 - 2x for y in (2)

3x - 2(7 - 2x) = 3

3x - 14 + 4x = 3

7x + 3 + 14 = 17

x = \(\frac{17}{7}\)

Hence, 7 x \(\frac{17}{7}\)

= 17 - 10

= 7

794.

Find the values of y for which the expression \(\frac{y^2 - 9y + 18}{y^2 + 4y - 21}\) is undefined

A.

6, -7

B.

3, -6

C.

3, -7

D.

-3, -7

Correct answer is C

\(\frac{y^2 - 9y + 18}{y^2 + 4y - 21}\)

Factorize the denominator;

Y2 + 7y - 3y - 21

= y(y + 7) -3 (y + 7)

= (y - 3)(y + 7)

Hence the expression \(\frac{y^2 - 9y + 18}{y^2 + 4y - 21}\) is undefined

when y2 + 4y - 21 = 0

ie. y = 3 or -7

795.

The roots of a quadratic equation are \(\frac{4}{3}\) and -\(\frac{3}{7}\). Find the equation

A.

21x2 - 19x - 12 = 0

B.

21x2 + 37x - 12 = 0

C.

21x2 - x + 12 = 0

D.

21x2 + 7x - 4 = 0

Correct answer is A

Let x = \(\frac{4}{3}\), x = -\(\frac{3}{7}\)

Then 3x = 4, 7x = -3

3x - 4 = 0, 7x + 3 = 0

(3x - 4)(7x + 3) = 0

21x2 + 9x - 28x - 12 = 0

21x2 - 19x - 12 = 0