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 answer step by step:
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. The answer: 5.