There were some apples, passion fruits and mangosteens. The number of apples was two times the number of passion fruits. The total number of apples and passion fruits was half of the number of mangosteens. There were 189 fruits altogether. All the mangosteens were sold at 6 for $13. How much money was collected from the sale of the mangosteens?
Number of passion fruits = 1 u
Number of apples = 2 u

Total number of passion fruits and apples
= 1 u + 2 u
= 3 u

Number of mangosteens
= 2 x 3 u
= 6 u

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

9 u = 189

1 u = 189 ÷ 9 = 21

Number of mangosteens sold
= 6 u
= 6 x 21
= 126

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

Amount collected from the sale of mangosteens
= 21 x 13
= $273

Answer(s): $273