Solve the Problem $$\mathrm { F } ( \mathrm { t } ) = 1 - \mathrm { e } ^ { - 0.25 \mathrm { t } }$$

Multiple Choice

Solve the problem.
-Between 7:00 AM and 8:00 AM, trains arrive at a subway station at a rate of 15 trains per hour (0.25 trains per minute) . The following formula from statistics can be used to determine the probability that a train will arrive within t
Minutes of 7:00 AM. $$\mathrm { F } ( \mathrm { t } ) = 1 - \mathrm { e } ^ { - 0.25 \mathrm { t } }$$ Determine how many minutes are needed for the probability to reach 20%.

A) 0.89 min
B) 2.35 min
C) 5.34 min
D) 4.12 min