A cashier found that he was often asked to give change for a dollar to people who had made no purchases but wanted 20 cents for a telephone call. He started thinking one day about the number of ways he could make change. If he gave no more than four of any type of coin and made sure that the person received coins to make exactly 20 cents in order to make the phone call in how many different ways could he give change for a dollar (in other words,four quarters would not be allowed because the person would not have 20 cents for the phone call
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pennies are out. you could only give out 4 and 100-4=96...no other combination of coins will give us that sum.
Q=quarters D=dimes N=nickels
1Q + 4D + 4N will NOT work therefore you will ALWAYS need more than 1Q.
2Q + 4D + 4N will NOT work so you will always have to have either 3D and 4N or 4D and 2N with 2Q.
3Q + 4N will NOT work so you will ALWAYS need dimes
so the only possible ways are:
1) 2Q + 3D + 4N
2) 2Q + 4D + 2N
3) 3Q + 2D + 1N
4)3Q + 1D + 3N
hope that helped! :D
Q=quarters D=dimes N=nickels
1Q + 4D + 4N will NOT work therefore you will ALWAYS need more than 1Q.
2Q + 4D + 4N will NOT work so you will always have to have either 3D and 4N or 4D and 2N with 2Q.
3Q + 4N will NOT work so you will ALWAYS need dimes
so the only possible ways are:
1) 2Q + 3D + 4N
2) 2Q + 4D + 2N
3) 3Q + 2D + 1N
4)3Q + 1D + 3N
hope that helped! :D