Question
In how many ways can you change a $50 bill using $20 bills, $10 bills, $5 bills, $2 bills, and $1 bills ?
Answers
Lambert
I don't know the answer
oobleck
well, just start listing them:
20, 20, 10
20, 20, 5, 2, 2, 1
20, 20, 5, 2, 1, 1, 1
and so on.
At each step, substitute smaller bills for larger ones.
Without going through the whole list, you should see a pattern in how many new ways come from replacing a bill with smaller ones.
20, 20, 10
20, 20, 5, 2, 2, 1
20, 20, 5, 2, 1, 1, 1
and so on.
At each step, substitute smaller bills for larger ones.
Without going through the whole list, you should see a pattern in how many new ways come from replacing a bill with smaller ones.