Ashley just invested $9900 in a mutual fund. If the fund's manager expects a growth rate of 6% each year, how long will it take for Ashley's investment to reach a value of $16000? How about a value of $25000? Express your answers in years.

3 is the greatest number of book shelves Andy can use. I solved this by finding the greatest comment factor of 9 and 6, which turned out to be 3.
6/3=2(reading books per shelf)
9/3=3(math books per shelf)
Every shelf there are two reading books and 3 math books