Problem Solving - Sharing Money

Question

If Will gives Molly $9, he will have the same amount of money she has. If Molly gives Will $9, the ratio of the money she has to the money Will has will be 1:2. How much money does Will have in the beginning?

Answer 1

Not sure what tools you have to solve this "elementary problem.

Will has $18 more than Molly. W - 9 = M + 9 → W = M + 18.

If Molly gives $10 to Will (M - 10 and W + 10) then Will (W + 10) has twice Molly (M - 10) →

W + 10 = 2(M - 10) or

W + 10 = 2M - 20. yet W = M + 18

M + 18 + 10 = 2M - 20

M + 28 = 2M - 20

48 = M

Molly has $48 and Will has $66.

Check:

66 - 9 = 57

48 + 9 = 57

48 - 10 = 38

66 + 10 = 76

QED