There were some pears, starfruits and oranges. The number of pears was two times the number of starfruits. The total number of pears and starfruits was one-quarter of the number of oranges. There were 150 fruits altogether. All the oranges were sold at 5 for $13. How much money was collected from the sale of the oranges?
Number of starfruits = 1 u
Number of pears = 2 u

Total number of starfruits and pears
= 1 u + 2 u
= 3 u

Number of oranges
= 4 x 3 u
= 12 u

Total number of fruits
= 1 u + 2 u + 12 u
= 15 u

15 u = 150

1 u = 150 ÷ 15 = 10

Number of oranges sold
= 12 u
= 12 x 10
= 120

Number of sets of 5 oranges
= 120 ÷ 5
= 24

Amount collected from the sale of oranges
= 24 x 13
= $312

Answer(s): $312