coin selection

Question

selecting three (3) coins, but assume that there are 5 dimes, 3 nickels, and 2 quarters.

In how many possible ways can the selection be made so that the value of the coins is at least 25 cents?

Answer 1

Hi Alex,

 

We'll do an iterative process of all good combinations in descending sequence of the number of coins going from the highest denomination to the lowest denomination.  

 

The results are tabulated below:

 

1.  Q-2  D-1  N-0

2.  Q-2  D-0  N-1

3.  Q-1  D-2  N-0

4.  Q-1  D-1  N-1

5.  Q-1  D-0  N-2

6.  Q-0  D-3  N-0

7.  Q-0  D-2  N-1

 

The tabulated results show 7 ways to combine any 3 coins to give a minimum value of 25 cents.

 

Thanks for submitting this problem.

 

God bless, Jordan.