Answer: There are 10 different ways!
Explanation:
You need to find non-negative numbers N, D, and Q so that:
5N + 10D + 25Q = 50
N + 2D + 5Q = 10
Q = 0 , 1 , 2
If Q = 1, then you have:
N + 2D = 5
Q = 1 , D = 2 , N = 1
Q = 1 , D = 1 , N = 3
Q = 1 , D = 0 , N = 5
N + 2D = 10
This gives the last solutions:
Q = 0 , D = 5 , N = 0
Q = 0 , D = 4 , N = 2
Q = 0 , D = 3 , N = 4
Q = 0 , D = 2 , N = 6
Q = 0 , D = 1 , N = 8
Q = 0 , D = 0 , N = 10
