Answer:
Step1- If she makes $6 for an hour then how much will she gain from 15 hours? So we multiply 6x15=$90. You can use cross multiplication if u are confused on what to multiply:
1hour - $6
15hours-$?
Step2- How much is still needed to gain $200?
So we subtract the total with the amount we got to find out how much is still left: $200-$90=$110
Step3- Therefore, for how many hours should she clean to obtain $110?
1hour - $7
?hours-$110
$110/7=amount of hours needed to obtain $110
15.7hours and u can round it off to 16