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.

1,226.

Simplify: \(\frac{x^2 - y^2}{(x + y)^2} \div \frac{(x - y)^2}{(3x + 3y)}\)

A.

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

B.

x + y

C.

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

D.

x - y

Correct answer is C

\(\frac{x^2 - y^2}{(x + y)^2} \div \frac{(x - y)^2}{(3x + 3y)}\)

\(\frac{(x + y)(x - y)}{(x + y)(x + y)}\div \frac{(x - y)(x - y)}{3(x + y)}\)

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

1,227.

Four oranges sell for Nx and three mangoes sell for Ny. Olu bought 24 oranges and 12 mangoes. How much did he pay in terms of x and y?

A.

N94x + 6y)

B.

N(6x + 4y)

C.

N(24x + 12y)

D.

N(12x + 24y)

Correct answer is B

4 oranges sell for Nx, 1 orange will sell for \(\frac{Nx}{4}\)

24 oranges will sell for: \(\frac{Nx}{4} \times 24\) = n6x

3 mangoes sell for Ny, 1 mango will sell for \(\frac{Ny}{3}\)

12 mangoes will sell for \(\frac{Ny}{3} \times 12\) = 4Ny

total money pay N6x + N4y = N(6x + 4y)

1,228.

A sales boy gave a change of N68 instead of N72. Calculate his percentage error

A.

4%

B.

5\(\frac{5}{9}\)%

C.

5\(\frac{15}{17}\)%

D.

7%

Correct answer is B

% error = \(\frac{error}{\text{actual value}} \times 100\)

error = N72 - N68 = 4

actual value = N72

%error = \(\frac{4}{72} \times 100\)

= \(\frac{100}{18} = \frac{50}{9}\) = 5\(\frac{5}{9}\)%

1,229.

If \(\sqrt{50} - K\sqrt{8} = \frac{2}{\sqrt{2}}\), find K

A.

-2

B.

-1

C.

1

D.

2

Correct answer is D

\(\sqrt{50} - K\sqrt{8} = \frac{2}{\sqrt{2}}\)

\(\sqrt{50} - \frac{2}{\sqrt{2}}\) = K\(\sqrt{8}\)

= \(\sqrt{2} \times 25 - \frac{2}{\sqrt{2}}\)

= K \(\sqrt{4 \times 2}\)

\(\frac{5\sqrt{2}}{1} - \frac{2}{\sqrt{2}}\) = 2K\(\sqrt{2}\)

\(\frac{5\sqrt{4} - 2}{\sqrt{2}} = 2K\sqrt{2}\)

\(\frac{10 - 2}{\sqrt{2}} = 2K \sqrt{2}\)

\(\frac{8}{\sqrt{2}} = \frac{2K\sqrt{2}}{1}\)

= 2k\(\sqrt{2} \times \sqrt{2}\) = 8

2k \(\sqrt{4}\) = 8

2k x 2 = 8

4k = 8

k = \(\frac{8}{4}\)

k = 2

1,230.

If Un = n(n2 + 1), evaluate U5 - U4

A.

18

B.

56

C.

62

D.

80

Correct answer is C

Un = n(n2 + 1)

U5 = 5(2 + 1)

= 5(25 + 1)

= 5(26) = 130

U4 = 4(42 + 1) = 4(16 + 1)

= 4(17) = 68

U5 - U4 = 130 - 68

= 62