i think i worked it out
the first part is just, for eg, 20 cents
20x = 1000
so 50x 20 cent coins will give 10 dollars
then for the second part, u do it with all the combos
for eg, for the combination of 20cent donimations and 50c coins
wed go 20x + 50y = 1000
x = 1000 - 50y / 20
so the...