Danho

Paper 1 · November 2021 · Probability

An ice cream vendor's sales are 40% chocolate, 35% vanilla and 25% peach. The probability of a cone sale is 0.80 for chocolate, 0.60 for vanilla and 0.40 for peach. What is the overall probability that a randomly selected sale is by cone?

A0.58
B0.60
C0.63
D0.67

Explanation

By the law of total probability, P(cone)=0.40(0.80)+0.35(0.60)+0.25(0.40)=0.32+0.21+0.10=0.63P(\text{cone}) = 0.40(0.80) + 0.35(0.60) + 0.25(0.40) = 0.32 + 0.21 + 0.10 = 0.63.

Derived from ZIMSEC Statistics Paper 1, November 2021, Q2

View this paper's sittings and topics→

More questions from this paper

Get the full paper, not just one question

Danho has every sitting for this paper, with your progress tracked question by question, offline.