1.

How many different collections of 3 coins can be formed if the coins can be pennies, nickels, dimes, quarters or half dollars?

Answer»

So
p + 5n + 10d + 25Q + 50 HD = 100

If we evaluate the EQUATION (mod 5) we get
p = 0 (mod 5)
i.e. p = 0, 5, 10, 15, ... but SINCE we can only have 19 coins, there is at most 15 pennies

Therefore, p = 0, 5, 10, or 15. i.e. p = 5K where k = 0,1,2,3


Discussion

No Comment Found

Related InterviewSolutions