A fruit seller sells only mangoes and pears. The ratio of mangoes to pears is 2 : 5. A total of 240 fruits are added. The number of mangoes becomes 4 times as many as before and the number of pears becomes 3 times as many as before. How many fruits are there at first?

	Comparing mangoes at first and in the end	Mangoes	Pears	Comparing pears at first and in the end
Before	1x2 = 2 u	2 u	5 u	1x5 = 5 u
Change		+ 240
After	4x2 = 8 u	8 u	15 u	3x5 = 15 u

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

The number of mangoes at first is repeated. Make the number of mangoes at first the same. LCM of 1 and 2 is 2.

Number of fruits at first
= 2 u + 5 u
= 7 u

Number of fruits in the end
= 8 u + 15 u
= 23 u

Number of fruits added
= 23 u - 7 u 
= 16 u

16 u = 240

1 u = 240 ÷ 16 = 15

Number of fruits at first
= 7 u
= 7 x 15
= 105

Answer(s): 105