Adam, Bryan and Charlie have $1638.
After Adam spends ³₄ of his money,
Bryan spends ⁴₇ of his money and
Charlie spends ¹₅ of his money,
they have equal amount of money left.
Find the total amount that the 3 children spend.

	Adam	Bryan	Charlie
Before	4 x 12 = 48 u	7 x 4 = 28 u	5 x 3 = 15 u
Change	- 3 x 12 = - 36 u	- 4 x 4 = - 16 u	- 1 x 3 = - 3 u
After	1 x 12 =  12 u	3 x 4 = 12 u	4 x 3 = 12 u

The lowest common multiple of 1, 3 and 4 is 12.

Fraction of the amount left after Adam spends his money
= 1 - ³₄
= ¹₄

Fraction of the amount left after Bryan spends his money
= 1 - ⁴₇
= ³₇

Fraction of the amount left after Charlie spends his money
= 1 - ¹₅
= ⁴₅

Make the numerators the same.
1 x 124 x 12 of Adam's amount = 3 x 47 x 4 of Bryan's amount = 4 x 35 x 3 of Charlie's amount
1248 of Adam's amount = 1228 of Bryan's amount = 1215 of Charlie's amount

Total amount that they have at first
= 48 u + 28 u + 15 u
= 91 u

91 u = 1638

1 u = 1638 ÷ 91 = 18

Amount that Adam spends
= 48 u - 12 u
= 36 u

Amount that Bryan spends
= 28 u - 12 u
= 16 u

Amount that Charlie spends
= 15 u - 12 u
= 3 u

Amount that they spend
= 36 u + 16 u + 3 u
= 55 u
= 55 x 18
= $990

Answer(s): $990