The average number of lemons in Box A, Box B and Box C is 30 and it is 10 more than the average number of apples in the 3 boxes. ¹₅ of the apples are in Box A and the apples in Box A is 30% of the number of apples in Box B. If each box has the same number of fruits, what percentage of the fruits in Box C are lemons?
Average number of apples
= 30 - 10
= 20

Total number of apples
= 3 x 20
= 60

Total number of lemons
= 3 x 30 
= 90

Total number of fruits
= 60 + 90
= 150

Number of fruits in each box
= 150 ÷ 3
= 50

Apples in Box A	Apples in Box B	Apples in Box C	Total apples
1x3	4x3		5x3
3x1	10x1
3 u	10 u	2 u	15 u

30% = ³⁰₁₀₀ = ³₁₀

The number of apples in Box A is repeated.  Make the number of apples in Box A the same.  LCM of 1 and 3 is 3. 

Total number of apples
= 3 u + 10 u + 2 u
= 15 u

15 u = 60

1 u = 60 ÷ 15 = 4

Number of apples in Box C
= 2 u
= 2 x 4
= 8

Number of lemons in Box C
= 50 - 8
= 42

Percentage of the fruits in Box C are lemons
= ⁴²₅₀ x 100%
= 84%

Answer(s): 84%