Gary is a teacher and earned half what Mary earned for 5 years. Mary spent 1/3 of her money. Gary spent 1/4 every year for those 5 years. Gary has $75000 after 5 years. How much does Mary have?

The answer is $133,333 dollars.
Pls explain working out

m = 2g

3/4 g * 5 = 75000
g = 20000
so Mary earned 40,000 per year
Now you can see how to get the answer