There were some lemons, apples and oranges. The number of lemons was two times the number of apples. The total number of lemons and apples was one-third of the number of oranges. There were 168 fruits altogether. All the oranges were sold at 6 for $6. How much money was collected from the sale of the oranges?
Number of apples = 1 u
Number of lemons = 2 u

Total number of apples and lemons
= 1 u + 2 u
= 3 u

Number of oranges
= 3 x 3 u
= 9 u

Total number of fruits
= 1 u + 2 u + 9 u
= 12 u

12 u = 168

1 u = 168 ÷ 12 = 14

Number of oranges sold
= 9 u
= 9 x 14
= 126

Number of sets of 6 oranges
= 126 ÷ 6
= 21

Amount collected from the sale of oranges
= 21 x 6
= $126

Answer(s): $126