Step-by-step explanation:
1a. Would be 3 hours and 20 mins because you would times 20 by 10 which would then equal 200 minutes and then you would have to convert it to hours and minutes (60 mins in a hour).
1b. Would be 5 hours and you would solve it the same as 1a but different numbers.
1c. Would be 9 hours and 10 mins and once again you would solve it the same as 1a.
2. Your friend should reapply their sunscreen first because 25x 10= 250 mins 250 mins = 4 hours and 10 mins and 15x10=150 mins= 2 hour and 30 mins and since you applied it an hour earlier you would subtract an hour from your time which would then be 3 hours and 10 mins which is more time then your friends.
11:30 A.M. because two hours ahead of 9 is 11 and then you would need to add 30 mins to that.
