John had only 10-dollar notes and David had only 5-dollar notes. The number of notes John had was 2/3 of the number of notes David had. After John had given David $450 in $10 notes, the number of notes John had was 1/6 of the number of notes David had. How much money did David have in the end?
Let the number of $10 notes that John had==J
Let the number of $5 notes that David had==D
John had ==2/3D
2/3D - 45 ==1/6 *[D + 45], solve for D
D==105 - number of $5 notes that David originally started with.
105 $5 notes + 45 $10 notes ==150 notes altogether, worth==105 *5 + 45 *10 ==$975 in value.
John was left with 1/6 * [105 + 45] ==25 * $10 notes worth==$250 in value.
