Let us denote the number of oranges with X and the number of apples with Y. The The ratio between X and Y indicates how many times the X contains Y. It is noted with: X/Y .
In our case X=60 and Y=18
60/18
Both 60 and 18 is divided with 6: 60:6=10, 18:6=3, which makes the correct answer for the ratio of oranges to apples: 10/3
