###Human: Carol has $60 and saves $9 per week. Mike has $90 and saves $3 per week. How many weeks before Carol and Mike both have the same amount of money?, ### Assistant: Let x = the number of weeks.
60 + 9x = 90 + 3x to set them equal.
9x = 30 + 3x
6x = 30
x = 5
In 5 weeks they will have equal money. 
 So the answer is :  5