Answer:
P = 0.23375
Step-by-step explanation:
given,
you remain in store for 15 minutes.
you friend remains in store for 10 minutes.
probability that they are store at the same time
from the graph attached below
shaded region shows the required probability,.
probability of the square = 1
probability of the shaded region = 1 - (area of lower triangle - area of upper triangle)
area of lower triangle = \dfrac{1}{2}(0.85)(0.85)
= 0.36125
area of the upper triangle = \dfrac{1}{2}(0.9)(0.9)
= 0.405
probability of the shaded region = 1 - (0.36125+0.405)
= 0.23375
