Neil needs to mail a CD to friend. he uses 40-cent stamps and 7-cent stamps to pay $2.56 in postage. how many of each stamp did he use

Answer:He used five 40-cent stamps and eight 7-cent stamps.

Step-by-step explanation:

Let x represent the number of 40-cent stamps that he used.

Let y represent the number of 7-cent stamps that he used.

41 cents = 40/100 = $0.40

7 cents = 7/100 = $0.07

He uses 40-cent stamps and 7-cent stamps to pay $2.56 in postage. It means that

0.4x + 0.07y = 2.56

Multiplying through by 100, it becomes

40x + 7y = 256

7y = 256 - 40x

We would test for corresponding values of x and y that satisfies the equation and they must be whole numbers.

If x = 4,

7y = 256 - 40 * 4 = 96

y = 96/7 = 13.71

If x = 5,

7y = 256 - 40 * 5 = 56

y = 56/7 = 8

Answer: He simply used five forty cent stamps and eight seven cent stamps.

Step-by-step explanation:

Multiply 5*.40 and you should get 2/$2.00

Next, multiply 5*7 and you should get 56

Last, add the $2 and 56 cent and you should get $2.56 as your final answer.