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?
Let's be accurate as possible and think first.
5
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