There were some lemons and oranges in Box K and Box L. In Box K, the ratio of the lemons to the number of oranges was 2 : 1. In Box L, the ratio of the number of lemons to the number of oranges was 3 : 1. There were 3 times as many fruits in Box K as in Box L. After another 50 oranges were put into Box L, the ratio of the number of lemons to the number of oranges in Box L became 1 : 2. How many fruits were there in Box L in the end?

Box K		Box L
3x4 = 12 u		1x4 = 4 u
Lemons	Oranges	Lemons	Oranges
2x4	1x4	3	1
8 u	4 u	3 u	1 u

The total number of fruits in Box K is repeated.  Make the total number of fruits in Box K the same.  LCM of 3 and 3 is 12.

The total number of fruits in Box L at first is repeated.  Make the total number of fruits in Box L the same.  LCM of 1 and 4 is 4.

	Box K		Box L
	Lemons	Oranges	Lemons	Oranges
Before	8 u	4 u	3 u	1 u
Change				+ 50
After	8 u	4 u	1x3 = 3 u	2x3 = 6 u

Number of lemons in Box L remains unchanged.  Make the number of lemons in Box L the same.  LCM of 3 and 1 is 3.

Number of oranges put into Box L
= 6 u - 1 u
= 5 u

5 u = 50

1 u = 50 ÷ 5 = 10

Number of fruits in Box L in the end
= 3 u + 6 u
= 9 u
= 9 x 10
= 90

Answer(s): 90