please answer this question.

You are 40 years old and want to set aside enough money so that you can help pay for your kids college. You make an annual deposit at the beginning of each year for the next 7 years into a retirement account and it is expected to grow at 10% per year. When your first child goes to college in year 8 you will need to withdrawal $18,000 annually...out-of-state tuition. In year 10 your second child will go to college, but she decides to stay in-state and your withdrawals will total $25,000 per year for both kids when they are in school at the same time. You are only paying for a 4 year degree. Your account balance continues to grow at 10% per year. How much do you need to deposit annually in the account for 7 years to have enough to pay for college