look at the picture
Please help

Answer:
The probability that Aaron goes to the gym on exactly one of the two days is 0.74
Step-by-step explanation:
Let P(Aaron goes to the gym on exactly one of the two days) be the probability that Aaron goes to the gym on exactly one of the two days.
Then
P(Aaron goes to the gym on exactly one of the two days) =
P(Aaron goes to the gym on Saturday and doesn't go on Sunday) +
P(Aaron doesn't go to the gym on Saturday and goes on Sunday)
P(Aaron goes to the gym on Saturday and doesn't go on Sunday) =
P(the probability that Aaron goes to the gym on Saturday)×P(If Aaron goes to the gym on Saturday the probability that he does not go on Sunday)=
0.8×0.7=0.56
Thus, P(Aaron doesn't go to the gym on Saturday and goes on Sunday) = P(The probability that Aaron doesn't go to the gym on Saturday)×P(if Aaron does not go to the gym on Saturday the probability he goes on Sunday)
=0.2×0.9=0.18
Then
P(Aaron goes to the gym on exactly one of the two days) =0.56 + 0.18 =0.74