All use computer

It is reported that 72% of working women use computers at work. Choose three women at random, and find the probability that all three women use a computer in their jobs.

Correct answer:

p =  0.3732

Step-by-step explanation:

$$\begin{gathered} q=72\%=\frac{72}{100}=\frac{18}{25}=0.72 \\ {C}_3(3)=\left(\genfrac{}{}{0ex}{}{3}{3}\right)=\frac{3!}{3!(3-3)!}=\frac{1}{1}=1 \\ p=\left(\genfrac{}{}{0ex}{}{3}{3}\right)\cdot q^3\cdot (1-q{)}^{3-3}=1\cdot 0.72^3\cdot (1-0.72{)}^{3-3}\doteq 0.3732 \\ \text{ Verifying Solution: } \\ {p}_2=q^3=0.72^3\doteq 0.3732 \end{gathered}$$

Try another example