1993 - WAEC Mathematics Past Questions and Answers - page 5

= 2 + 4 + 3 + 6 + 6 + 2 + 1

= 24 students

= 2 + 4 + 3 + 6

= 15 students scored less than 7 marks.

S = {20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30}

n(S) = 11

P = {23, 29}

n(P) = 2

Prob(P) = \(\frac{2}{11}\)

Prob(less than 3) = \(\frac{2}{6}\)

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

Prob(even number in single toss) = \(\frac{3}{6}\)

= \(\frac{1}{2}\)

No of possible outcome = 36

Required outcome (R) = {(1, 6), (6, 1), (2, 5), (5, 2), (3, 4), (4, 3)}

n(R) = \(\frac{6}{36}\)

= \(\frac{1}{6}\)

Prob(obtaining a 2) = \(\frac{30}{200}\)

= \(0.15\)

Prob(less than 3) = \(\frac{25 + 30}{200}\)

= \(\frac{11}{40}\)

= 0.275