Question

If you have only 5¢, 20¢ and 50¢ coins, in how many ways can you make up exactly $1?

Answer 1

50+50

50+20+5+5+5+5+5+5

50+20+20+5+5

3 ways with 50, 20 and 5

20+20+20+20+20

20+20+20+20+5+5+5+5

20+20+20+5+5+5+5+5+5+5+5

20+20+5+5+5+5+5+5+5+5+5+5+5+5

20+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5

5 ways with 20 and 5

50+5+5+5+5+5+5+5+5+5+5

1 way with 50 and 5

Then 3+5+1 =9 ways in total

Hope this help!