WAEC Further Mathematics Past Questions & Answers - Page 90

446.

The distance s in metres covered by a particle in t seconds is \(s = \frac{3}{2}t^{2} - 3t\). Find its acceleration.

A.

\(1 ms^{-2}\)

B.

\(2 ms^{-2}\)

C.

\(3 ms^{-2}\)

D.

\(4 ms^{-2}\)

Correct answer is C

The two time differentiation of distance with respect to time will give the acceleration.

\(s = \frac{3}{2}t^{2} - 3t\)

\(\frac{\mathrm d s}{\mathrm d t} = v = 3t - 3\)

\(\frac{\mathrm d v}{\mathrm d t} = a = 3\)

447.

A box contains 4 red and 3 blue identical balls. If two are picked at random, one after the other without replacement, find the probability that one is red and the other is blue.

A.

\(\frac{4}{7}\)

B.

\(\frac{2}{7}\)

C.

\(\frac{1}{7}\)

D.

\(\frac{1}{12}\)

Correct answer is A

P(one blue, other red) = P(1st red then blue) or P(1st blue then red)

= \((\frac{4}{7} \times \frac{3}{6}) + (\frac{3}{7} \times \frac{4}{6})\)

= \(\frac{2}{7} + \frac{2}{7} = \frac{4}{7}\)

448.

Find the acute angle between the lines 2x + y = 4 and -3x + y + 7 = 0.

A.

40°

B.

44°

C.

45°

D.

54°

Correct answer is C

\(2x + y = 4 \equiv y = 4 - 2x \implies m_{1} = -2\)

\(-3x + y + 7 = 0 \equiv y = -7 + 3x \implies m_{2} = 3\)

\(\tan \theta = \frac{m_{1} - m_{2}}{1 - m_{1}m_{2}} = \frac{-2 - 3}{1 - (-2)(3)} = \frac{-5}{-5} = 1\)

\(\tan \theta = 1 \implies \theta = 45°\)

449.

Find the number of different arrangements of the word IKOTITINA.

A.

30240

B.

60840

C.

120960

D.

362880

Correct answer is A

IKOTITINA has 9 letters with 2Ts and 3Is. Therefore, the number of different arrangements

= \(\frac{9!}{2!3!} = \frac{9.8.7.6.5.4}{2} = 30240\)

450.

A straight line makes intercepts of -3 and 2 on the x- and y- axes respectively. Find the equation of the line.

A.

2x + 3y + 6 = 0

B.

3x - 2y - 6 = 0

C.

-3x + 2y - 6 = 0

D.

-2x + 3y - 6 =0

Correct answer is D

Equation of a straight line : y = mx + b

where m = the slope of the line

b = y- intercept

Given the two points (-3, 0) and (0, 2).

\(m = \frac{2 - 0}{0 - (-3)} = \frac{2}{3}\)

\(y = \frac{2}{3}x + 2 \implies 3y = 2x + 6\)

\(-2x + 3y - 6 = 0\)