Justin and Luis had 74 marbles in total. Luis had 14 marbles more than Justin at first. After Justin and Luis played a game with Cindy, Justin had ⁵₁₂ as many marbles as Luis. If Justin lost as many marbles as Luis to Cindy, find the number of marbles that Justin lost to Cindy.

	Justin	Luis	Difference
Before	1 u	1 u + 14	14
Change	- ?	- ?
After	5 p	12 p	7 p

Total number of marbles at first
= 1 u + 1 u + 14 
= 2 u + 14

2 u + 14 = 74
2 u = 74 - 14
2 u = 60

1 u = 60 ÷ 2 = 30

Since Justin lost the same number of marbles as Luis, the difference in the number of marbles between Justin and Luis at first and in the end remains the same.

Difference in the number of marbles in the end
= 12 p - 5 p
= 7 p

7 p = 14

1 p = 14 ÷ 7 = 2

Number of marbles that Justin lost to Cindy
= 1 u - 5 p
= 30 - 5 x 2
= 30 - 10
= 20

Answer(s): 20