Jeremy had three boxes, containing a total of 1100 styrofoam cups. The number of styrofoam cups in Box J to the total number of styrofoam cups was 3 : 10. He sold 485 styrofoam cups from Box K and sold ¹₄ of the styrofoam cups in Box L. The number of styrofoam cups left in Box K to the number of styrofoam cups left in Box L was 5 : 1. How many styrofoam cups were there in Box K at first?

	Box J	Box K	Box L	Total
Before	3 u	7 u (770)		10 u (1100)
		15 p + 485	4 p
Change		- 485	- 1 p
			3 p
After		5x3 = 15 p	1x3 = 3 p

10 u = 1100
1 u = 1100 ÷ 10 = 110

Number of styrofoam cups in Box K and Box L at first
= 7 u
= 7 x 110
= 770

The number of cups left in L is the repeated identity.
LCM of 1 and 3 = 3

15 p + 485 + 4 p = 770
15 p + 4 p = 770 - 485
19 p = 285

1 p = 285 ÷ 19 = 15

Number of cups in Box K at first
= 15 p + 485
= 15 x 15 + 485
= 225 + 485
= 710

Answer(s):710