Solve this problem by setting up ratios with the information you know.
You know:
- Eddie spent 3.75 total on chocolate and cake.
- He has 2/3 of his money left over after buying chocolate and cake
With this information, you can assume that he used 1/3 of his money.
With this set up a ratio comparing the numerical amount he spent to the ratio of his total money that he spent:
x= the total amount of money he started with.
Now cross multiply to come up with a final equation:
x = 3.75 × 3
Solve: x = 11.25
The original amount of money he started with was $11.25