There were some apples, mangoes and starfruits. The number of apples was two times the number of mangoes. The total number of apples and mangoes was half of the number of starfruits. There were 162 fruits altogether. All the starfruits were sold at 6 for $13. How much money was collected from the sale of the starfruits?
Number of mangoes = 1 u
Number of apples = 2 u

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

Number of starfruits
= 2 x 3 u
= 6 u

Total number of fruits
= 1 u + 2 u + 6 u
= 9 u

9 u = 162

1 u = 162 ÷ 9 = 18

Number of starfruits sold
= 6 u
= 6 x 18
= 108

Number of sets of 6 starfruits
= 108 ÷ 6
= 18

Amount collected from the sale of starfruits
= 18 x 13
= $234

Answer(s): $234