Juan and David had $106 altogether. David had $38 less than Juan. After David spent some money at the store, Juan had 3 times as much money as David. How much money had David spent at the store?
Let Juan's money ==J
David's money ==J - 38
J + J - 38 ==106, solve for J
2J ==106 + 38==144
J == 144 / 2 ==$72 - Juan's money
106 - 72 ==$34 - David's money
Let the amount spent by David==D
34 - D == 1/3 * 72==24
D ==34 - 24 ==$10 - what David spent at the store
+16 At the start, David has 34 dollars and Juan has 72 dollars. Juan's money stays the same after David spends some money, and we are told he has three times as much as David after David spends some of his money. 72/3 is 24 dollars, which is what David is left with. 34-24 is \(\boxed{10}\) dollars
- Eyedrop
