A fruit seller sells only mangosteens and mangoes. The ratio of mangosteens to mangoes is 3 : 5. A total of 26 fruits are added. The number of mangosteens becomes 2 times as many as before and the number of mangoes becomes 3 times as many as before. How many fruits are there in the end?

	Comparing mangosteens at first and in the end	Mangosteens	Mangoes	Comparing mangoes at first and in the end
Before	1x3 = 3 u	3 u	5 u	1x5 = 5 u
Change		+ 26
After	2x3 = 6 u	6 u	15 u	3x5 = 15 u

The number of mangoes at first is repeated.  Make the number of mangoes at first the same.  LCM of 1 and 5 is 5.

The number of mangosteens at first is repeated. Make the number of mangosteens at first the same. LCM of 1 and 3 is 3.

Number of fruits at first
= 3 u + 5 u
= 8 u

Number of fruits in the end
= 6 u + 15 u
= 21 u

Number of fruits added
= 21 u - 8 u 
= 13 u

13 u = 26

1 u = 26 ÷ 13 = 2

Number of fruits in the end
= 21 u
= 21 x 2
= 42

Answer(s): 42