If the ratio of Zoe; Hannah is 3:7 and Zoe got 24 than we have to divide the 24 by 3 so we can multiply it by 7. This is because since the Zoe is the 3 and it isn't a 1 it isn't the starting point for either of the ratios we cannot multiply the 24 by 7.
24 ÷ 3 = 8
Now we multiply the 8 by 7 so that we know have many tips Hannah made