pls help!!!!!

Joanne had 3/5 as much as Jean at first. After receiving $12 each, Joanne has 3/4 as much money as Jean.How much money did Joanne have at first?

As both receive the same amount, we can use the Constant Difference approach.

Joanne : Jean
3 : 5 (Difference 2units)

Joanne : Jean
3 : 4 (Difference 1unit)
6 : 8 (Difference 2units)

3units --> 12
1unit --> 4
Joanne had 3units at first --> 4x3 = $12

Sorry, still confuse on the second part. Why need to have (6:8)
& get the 3units??


Joanne : Jean
3 : 5 (Difference 2units)

Joanne : Jean
3 : 4 (Difference 1unit)
6 : 8 (Difference 2units)

This is the approach we take for Constant Difference questions. In short, the difference between the two people is the same before and after the change. Therefore, the difference in units, before and after, must also be the same. Since the difference in ratio, in the end, is only 1unit (4-3) we change the ratio to 6:4. Now the difference is 2 units.

You can find more explanation and questions in Chapter 2.6 of your +hinkingMath@onsponge.com book. If you want Constant Difference with whole numbers and ratios, you can refer to Chapter 1.4 and 3.5 respectively.