WAEC Mathematics Past Questions & Answers - Page 89

441.

If log 5.957 = 0.7750, find log \(3 \sqrt{0.0005957}\)

A.

4.1986

B.

2.9250

C.

1.5917

D.

1.2853

Correct answer is B

\(3 \sqrt{0.0005957}\)

\(\begin{array}{c|c} \log No(0.0005957) & \frac{1}{3} \log \frac{1}{3} \\ \hline (0.0005957)^{\frac{1}{3}} & 4.7750 \times \frac{1}{3} \\ & 6 + 2.7750 \\\hline & 3 \\\hline & 2.9250\end{array}\)

442.

If a number is selected at random from each of the sets p = {1, 2, 3} and Q = {2, 3, 5}, find the probability that the sum of the numbers is prime

A.

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

B.

1\(\frac{4}{9}\)

C.

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

D.

\(\frac{2}{9}\)

Correct answer is C

p = { 1, 2, 3}

Q = {2, 3, 5}

prob(prime number) = prob(1 and 2) or

= prob(2 and 3) or

= prob(3 and 2)

There are three possibilities of the sum being prime

Total possibility = 9

probability(sum being prime) = \(\frac{3}{9}\)

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

444.

In parallelogram PQRS, QR is produced to M such that |QR| = |RM|. What fraction of the area of PQMS is the area of PRMS?

A.

\(\frac{1}{4}\)

B.

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

C.

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

D.

\(\frac{3}{4}\)

Correct answer is C

There are 3 triangles: \(\bigtriangleup\)MRS, \(\bigtriangleup\) and \(\bigtriangleup\) PRQ

Area PRMS has 2 triangles: \(\bigtriangleup\) MRS and \(\bigtriangleup\) RSP

the fraction = \(\frac{2}{3}\)

445.

A chord subtends an angle of 120o at the centre of a circle of radius 3.5cm. Find the perimeter of the minor sector containing the chord, [Take \(\pi = \frac{22}{7}\)]

A.

14\(\frac{1}{3}\)cm

B.

12\(\frac{5}{6}\)cm

C.

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

D.

7\(\frac{1}{3}\)cm

Correct answer is A

perimeter of minor sector

2r + \(\frac{\theta}{360} \times 2 \pi r\)

= 2 x 3.5 + \(\frac{120^o}{360^o} \times 2 \frac{22}{7} \times 3.5\)

= 7 + \(\frac{154}{21}\)

= 7 + 7.33

= 14.33

= 14\(\frac{1}{3}\)cm