A fruit seller sells only guavas and kiwis. The ratio of guavas to kiwis is 1 : 2. A total of 48 fruits are added. The number of guavas becomes 3 times as many as before and the number of kiwis becomes 2 times as many as before. How many fruits are there at first?

	Comparing guavas at first and in the end	Guavas	Kiwis	Comparing kiwis at first and in the end
Before	1x1 = 1 u	1 u	2 u	1x2 = 2 u
Change		+ 48
After	3x1 = 3 u	3 u	4 u	2x2 = 4 u

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

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

Number of fruits at first
= 1 u + 2 u
= 3 u

Number of fruits in the end
= 3 u + 4 u
= 7 u

Number of fruits added
= 7 u - 3 u 
= 4 u

4 u = 48

1 u = 48 ÷ 4 = 12

Number of fruits at first
= 3 u
= 3 x 12
= 36

Answer(s): 36