WAEC Mathematics Past Questions & Answers - Page 268

1,336.

Simplify: \((2\frac{1}{6} - 1\frac{2}{3}) \div 2\frac{2}{3}\).

A.

3/16

B.

7/16

C.

1 13/24

D.

2 11/24

E.

10 2/5

Correct answer is A

\((2\frac{1}{6} - 1\frac{2}{3}) \div 2\frac{2}{3}\)

= \((\frac{13}{6} - \frac{5}{3}) \div \frac{8}{3}\)

= \(\frac{3}{6} \times \frac{3}{8}\)

= \(\frac{3}{16}\)

1,337.

Convert the decimal number 89 to a binary number

A.

101101

B.

111001

C.

1001001

D.

1001101

E.

1011001

Correct answer is E

No explanation has been provided for this answer.

1,338.

The 6th term of a G.P is \(\frac{-2}{27}\) and its first term is 18. What is the common ratio?

A.

-1/2

B.

-1/3

C.

1/4

D.

2

E.

3

Correct answer is B

a, ar, ar\(^2\), ar\(^3\), ar\(^4\), ar\(^5\)
6th term = ar\(^5\) = \(\frac{-2}{27}\)
1st term = a = 18
=> ar\(^5\)

= 18r\(^5\) =\(\frac{-2}{27}\)

r\(^5\) = \(\frac{-2}{27 * 18}\)

→ \(\frac{-1}{27 * 9}\)


r\(^5\) = \(\frac{-1}{243}\)


r = \(^5\)√[\(\frac{-1}{243}\)]

 

r = \(\frac{-1}{3}\)

1,339.

From a box containing 2 red, 6 white and 5 black balls, a ball is randomly selected. What is the probability that the selected ball is black?

A.

2/13

B.

5/13

C.

5/11

D.

5/6

E.

11/13

Correct answer is B

2r, 6w, 5b balls Total balls = 2 + 6 + 5 = 13 balls p(black) = 5/13

1,340.

Two fair dice are tossed together once. Find the probability that the sum of the outcome is at least 10.

A.

1/12

B.

5/ 36

C.

1/ 6

D.

1/4

E.

5/18

Correct answer is C

No explanation has been provided for this answer.