1/5 of Andrew's money was $12 more than 1/3 of Drake's money. When Andrew have Drake $50, both of them had the same amount of money in the end. How much did Andrew have at first?
1/5 of Andrew' money = 1/3 of Drake's money + $12
3/5 of Andrew's money = 3/3 of Drake's money + $36
Difference at first --> 2/5 of Andrew's money + $36
Difference at first --> $50 * 2
= $100
2/5 of Andrew's money + $36 = $100
$100 - $36 = $64
2/5 of Andrew's money = $64
1/5 of Andrew's money = $32
Andrew's money = $32 * 5
= $160
Andrew had $160 at first.
(1/5)A - 12 = (1/3)D multiply through by 3
(3/5)A - 36 = D (1)
A - 50 = D + 50 (2)
Sub (1) into (2) for D
A - 50 = (3/5)A - 36 + 50
A - (3/5)A = - 36 + 50 + 50
(2/5)A = 64
A = 64 (5/2) = 160 (dollars) = what Andrew started with
Proof
(1/5)A - 12 = (1/3) D
(1/5)A -12 = (1/3)((3/5)A - 36 ]
32 - 12 = (1/3) ( 96 - 36]
20 = (1/3) 60
20 = 20