There were some oranges, persimmons and apples. The number of oranges was two times the number of persimmons. The total number of oranges and persimmons was one-third of the number of apples. There were 168 fruits altogether. All the apples were sold at 7 for $8. How much money was collected from the sale of the apples?
Number of persimmons = 1 u
Number of oranges = 2 u

Total number of persimmons and oranges
= 1 u + 2 u
= 3 u

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

Number of sets of 7 apples
= 126 ÷ 7
= 18

Amount collected from the sale of apples
= 18 x 8
= $144

Answer(s): $144