Answer:
a) 4/15
b) 4/15
Step-by-step explanation:
maximum wait is 1 min,2 min,3 min,4 min,5 min,6 min,7 min,8 min,9 min,10 min,11 min,12 min,13 min,14 min,15 min =total 15 values
a) less than 4 min means he has to wait for 1 min, 2 min, 3 min, 4 min=total 4 values
Probability of wait for less than 4 minutes=4/15
b) more than 11 minutes wait means he has to wait for either 12 min, 13 min, 14 min, 15 min=4 values
Probability of wait for more than 11 minutes=4/15
