There were some mangosteens, mangoes and oranges. The number of mangosteens was three times the number of mangoes. The total number of mangosteens and mangoes was half of the number of oranges. There were 156 fruits altogether. All the oranges were sold at 8 for $15. How much money was collected from the sale of the oranges?
Number of mangoes = 1 u
Number of mangosteens = 3 u

Total number of mangoes and mangosteens
= 1 u + 3 u
= 4 u

Number of oranges
= 2 x 4 u
= 8 u

Total number of fruits
= 1 u + 3 u + 8 u
= 12 u

12 u = 156

1 u = 156 ÷ 12 = 13

Number of oranges sold
= 8 u
= 8 x 13
= 104

Number of sets of 8 oranges
= 104 ÷ 8
= 13

Amount collected from the sale of oranges
= 13 x 15
= $195

Answer(s): $195