Great algebra problem! We need to represent the unknown (which is the number of apples Rosa started with) with a letter, such as x.
After baking the pies, Rosa had (2x/3) apples left.
She gave her cousin (3/4) of (2x/3) apples. This comes out to x/2 apples, which is 9 apples, according to the problem.
Solve x/2 = 9 for x.
Be certain to check your answer!
After baking the pies, she had 2/3 of a bag left, which is (2/3) of 18, or 12.
Is (3/4) of 12 equal to 9?
Draw your own conclusions. Is x = 18 or not? Justify your answer.
