WAEC Mathematics 2014 Theory — Question 9
Question 9 of 23 from the West African Examinations Council (WAEC) Mathematics 2014 Theory paper, with the correct answer and a full explanation.
Advertisement
5. A building contractor tendered for two independent contracts, X and Y. The probability that he will win contract X is 0.5, and the probability that he will not win contract Y is 0.3. What is the probability that he will win: (a) both contracts; (b) exactly one of the contracts; (c) neither of the contracts?
Model answer
P(X)=0.5, so P(X')=0.5. P(Y')=0.3, so P(Y)=0.7. (a) P(both) = P(X)×P(Y) = 0.5×0.7 = 0.35 (b) P(exactly one) = P(X)P(Y') + P(X')P(Y) = (0.5×0.3)+(0.5×0.7) = 0.15+0.35 = 0.50 (c) P(neither) = P(X')×P(Y') = 0.5×0.3 = 0.15
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.