Cody and Oliver had 60 marbles in total. Oliver had 4 marbles more than Cody at first. After Cody and Oliver played a game with Esther, Cody had ⁷₉ as many marbles as Oliver. If Cody lost as many marbles as Oliver to Esther, find the number of marbles that Cody lost to Esther.

	Cody	Oliver	Difference
Before	1 u	1 u + 4	4
Change	- ?	- ?
After	7 p	9 p	2 p

Total number of marbles at first
= 1 u + 1 u + 4 
= 2 u + 4

2 u + 4 = 60
2 u = 60 - 4
2 u = 56

1 u = 56 ÷ 2 = 28

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

Difference in the number of marbles in the end
= 9 p - 7 p
= 2 p

2 p = 4

1 p = 4 ÷ 2 = 2

Number of marbles that Cody lost to Esther
= 1 u - 7 p
= 28 - 7 x 2
= 28 - 14
= 14

Answer(s): 14