Chapter 11.6, Problem 30SR

To determine

To find: Theprobability that at least $4$ of the next $5$ customers will donate more than the minimum.

Answer to Problem 30SR

The probability that at least $4$ of the next $5$ customers will donate more than the minimumis $0.4238$ .

Explanation of Solution

Given information:

The minimum amount for the car wash donated by $65\%$ of the customers.

The probability that at least $4$ of the next $5$ customers will donate more than the minimumis calculated as,

  $\begin{array}{c}P=P\left(4\right)+P\left(5\right)\\ =C{}_4{\left(0.65\right)}^4{\left(1-0.65\right)}^{5-4}+C{}_5{\left(0.65\right)}^5{\left(1-0.65\right)}^{5-5}\\ =0.4238\end{array}$

Thus, the probability that at least $4$ of the next $5$ customers will donate more than the minimumis $0.4238$ .