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i have 4 one cent stamps 3 five cent stamps and 3 twenty five cent stamps. how many different combinations can be made
with these stamps? Answer is 89 but whats the equation? Nick? 8th grade math.
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Let me reformulate the problem in more clear way.
"I have 4 one-cent coins; 3 five-cents coins; and 3 twenty-five cent coins.
How many different sums can I combine using these coins?"
1. You can get the sums of 1 cent, 2 cents, 3 cents and 4 cents
by combining one 1-cent coin, two 1-cent coins, three 1-cent coins and four 1-cent coins, respectively.
4 different sums.
2. You can get three sums of 5 cents, 10 cents, and 15 cents by combining . . . five-cent coins.
3 different sums.
3. You can get three sums of 25 cents, 50 cents, and 75 cents by combining . . . twenty-five-cent coins.
3 different sums.
4. 4*3 = 12 different sums by combining 4 one-cent coins with 3 five-cent coins.
5. 4*3 = 12 different sums by combining 4 one-cent coins with 3 twenty-five-cent coins.
6. 3*3 = 9 different sums by combining 3 five-cent coins with 3 twenty-five-cent coins.
7. 4*3*3 = 36 different sums by combining 3 five-cent coins with 3 five-cent coins and 3 twenty-five-cent coins.
8. Now add all these combinations:
4 + 3 + 3 + 12 + 12 + 9 + 36 = 79.
9. It is my answer.