Question 816698
Let p = purchase price, dollars per kg.,  when bought the 75 kg. of apples.
Want gain of 10% of 75*p dollars.  Five percent became "lost".  This means the fruit seller must sell 0.95(75) kg. for total revenue 75*p(1.10).  


Selling price for the needs to be high enough so that revenue is 75*p*(1.10).  Call this new selling price, s dollars per kg.


{{{0.95(75)s=75(p)(1.10)}}}
Again, that is the fruit sellers sells the available apples at price s so that revenue is ten percent more than what he paid originally for the 75 kg. of apples. Both prices are variables, and are unknown, based on the problem description.  You can easily solve for s, but it and p are still variables.