In a fraction when 3 is added to its numerator and denominator it becomes 4/5. And it becomes 1/2 when 2 is subtracted from both the numerator and denominator. Find the fraction.
There are 10 dozen apples, 15 dozen mangoes and 20 dozen oranges for selling. If 1/2, 1/3 and 1/4 of them are sold respectively. How many of the total fruits are remaining?