The Time Between Customer Arrivals at a Furniture Store Has $\theta = 8.5$

Multiple Choice

The time between customer arrivals at a furniture store has an approximate exponential distribution with mean $\theta = 8.5$ 8.5 minutes. If a customer just arrived, find the probability that the next customer will not arrive for at least 20 minutes.

A) 0.095089
B) 0.653770
C) 0.346230
D) 0.904911