The ratio of Kelly's money to Vera's money was 7:3. After Kelly spent $35, she had $9 more than Vera. How much money did each girl have at first?

Answer 1

There are a couple ways to do this:

1) Guess and check. So if there money is in the ratio of 7:3, then you could just do multiples of that ratio, so Kelly has $7 and Vera has $3, then Kelly has $14 and Vera has $6, then Kelly has $21 and Vera has $9. And you would continue like that until the second condition is met, which would be that when you subtract $35 from Kelly's amount, then it would be $9 more than Vera's amount.

2) Set up a system of equations. Let "x" be Kelly's initial amount of money and "y" be Vera's initial amount of money. We can write two equations. One equation will be based on the ratio, and the other equation will be based on the fact that subtracting 35 from Kelly's is equal to 9 more than Vera's amount.

If you have no idea how to build the equations in option 2, then go with option 1!