A fruit seller sells only passion fruits and pears. The ratio of passion fruits to pears is 3 : 4. A total of 60 fruits are added. The number of passion fruits becomes 3 times as many as before and the number of pears becomes 2 times as many as before. How many fruits are there at first?

	Comparing passion fruits at first and in the end	Passion Fruits	Pears	Comparing pears at first and in the end
Before	1x3 = 3 u	3 u	4 u	1x4 = 4 u
Change		+ 60
After	3x3 = 9 u	9 u	8 u	2x4 = 8 u

The number of pears at first is repeated.  Make the number of pears at first the same.  LCM of 1 and 4 is 4.

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

Number of fruits at first
= 3 u + 4 u
= 7 u

Number of fruits in the end
= 9 u + 8 u
= 17 u

Number of fruits added
= 17 u - 7 u 
= 10 u

10 u = 60

1 u = 60 ÷ 10 = 6

Number of fruits at first
= 7 u
= 7 x 6
= 42

Answer(s): 42