So since only 20 dollar bills and the other one is a 50 then
so we find some combos that will work five 20's make 100 we
notice that we can only have 20's in multipules of 5 to make 100's
becauause 4 20's makes 80 and 3 20's make 60 and 2 20's make40 and none
of those add to 50 evenly to make 100's (probably confusing but I hope you understand if you think about it)
so we have 5 20's =100 10 20's=200 15 20's=300 20 25 30 35 40 45 20's=900 50 20's=1000
so how many multiplules did we have? 10 but wait, if we havve 1000 in all 20's we still need at least one 50 so we subtract 100 900:9 answe ris 9 stacks
