WAEC Past Questions and Answers - Page 3739

18,691.

Find, correct to two decimal places, the mean of 9, 13, 16, 17, 19, 23, 24.

A.

23.00

B.

17.29

C.

16.50

D.

16.33

Correct answer is B

Mean \(= \frac{sum\hspace{1mm}of\hspace{1mm}all\hspace{1mm}the\hspace{1mm}numbers}{Total\hspace{1mm}Number}\\
\frac{9+13+16+17+19+23+24}{7}\\
\frac{121}{7}=17.2857=17.29\)

18,692.

Solve the equation 10-3x-x2 = 0

A.

x=2 or-5

B.

x= -2 or 5

C.

x = 1 or 10

D.

x = 2 or 5

Correct answer is A

10 – 3x - x2 = 0; 10 – 5x + 2x - x2 = 0
5(2 – x) + x(2 – x) = 0; (2 – x)(5 + x) = 0
2 – x = 0 or 5 + x = 0; x = 2 or x = -5

18,693.

Each interior angle of a regular polygon is 108°. How many sides has it?

A.

5

B.

7

C.

9

D.

14

Correct answer is A

The exterior angle of the polygon = 180 – 108 = 72°. The sum of exterior angle of the regular polygon = 360°
The number of sides \(=\frac{360}{72}=5\)

18,694.

Find the next two terms of the sequence 1, 5, 14, 30, 55, ...

A.

61,110

B.

67,116

C.

81,140

D.

91,140

Correct answer is D

\(1 + 2^2 = 5 + 3^2 = 14 + 4^2 = 30 + 5^2 = 55\)

\(55 + 6^2 = 91 + 7^2 = 140\).

91, 140 are the next two terms.

18,695.

lf \(log_q p= r\), express p in terms of q and r

A.

p =qr

B.

p =rq

C.

\(p = \frac{r}{q}\)

D.

p=qr

Correct answer is D

If \(log_q p\) = r convert from logarithm to indices
P = q\(^r\)