Answer:
24 Months
Explanation:
First you need to know how many books Ronnie read each month. 30 ÷ 15 = 2
Now you know Ronnie reads 2 books every month for 15 months.
So just take 48 ÷ 2 = 24
You take 48 because that's the total number of books so far and you divide it by 2, because he reads 2 books every month. That gives you a total of 24 months he has been with his book club.