Bessy has 7 times as much money as Bob but when each earns 4

Bessy has 7 times as much money as Bob, but when each earns $4, Bessy will have 3 times as much money as Bob. How much does each have before and after earning the $4?

Solution

Let the money with Bob be x

Money with Bessy = 7 * money with Bob = 7x

After earning 4$

Bessy money will become = 7x + 4

Bob money will become = x + 4

Now the equation will become

Bessy Money = 3 * Bob Money

7x + 4 = 3(x+4)

7x + 4 = 3x + 12

4x = 8

x = 2$

Money initial with Bob = 2$

Money initial with Bessy = 7x = 7 * 2 = 14$