Ashopkeeper bought some eggs at ¢15 each. six of them were broken while the rest were sold at ¢20 each. if he made a profit of $4.80, find how many eggs he bought.

In the given problem it is already stated that the cost of each eggs is 15 cent. Out the total eggs bought 6 were broken. The rest of the eggs were sold for 20 cents each and the profit made was $4.80.
Cost of the 6 broken eggs = (6 * 0.15)
                                           = 0.9 cents
Let us assume that the number of eggs bought = x
Then we can write the equation as
0.2x - (0.15x - 0.9) = 4.80
0.2x - 0.15x + 0.9 = 4.80
0.05x = 4.80 - 0.9
0.05x = 3.9
x = 3.9/0.05
   = 78
So the number of eggs bought by him is 78