There were 7 pineapples more than dragonfruits in a fruit stall. ²₅ of the dragonfruits and ³₇ of the pineapples were sold. Given that there was an equal number of dragonfruits and pineapples left, how many dragonfruits were there in the fruit stall at first?
Fraction of the dragonfruits left
= 1 - ²₅
= ³₅

Fraction of the pineapples left
= 1 - ³₇
= ⁴₇

The number of dragonfruits and pineapples left is the same. Make the number of pineapples and dragonfruits left the same. LCM of 3 and 4 is 12.

3x45x4 of the dragonfruits = 4x37x3 of the pineapples
1220 of the dragonfruits = 1221 of the pineapples

Number of dragonfruits at first = 20 u
Number of pineapples at first = 21 u

Number of more pineapples than dragonfruits at first
= 21 u - 20 u
= 1 u
= 7

Number of dragonfruits at first
= 20 u
= 20 x 7
= 140

Answer(s): 140