SOLUTION: Sarah and Keith purchased 40 stamps, a mixture of 44 cent and 28 cent stamps. Find the number of each type of stamp if they spent $16.80 **This is Urgent,,,I need HELP ASAP BAA

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Question 532160: Sarah and Keith purchased 40 stamps, a mixture of 44 cent and 28 cent stamps. Find the number of each type of stamp if they spent $16.80
**This is Urgent,,,I need HELP ASAP BAAAD**
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
x = number of 44-cent stamps
44x = value of the 44-cent stamps
y = number of 28-cent stamps
28y = value of the 28-cent stamps
.
x+y = 40 stamps
so
x = 40-y
and
y = 40-x
.
44x + 28y = 1680 cents spent buying the 40 stamps
.
Note that using cents for all of the units of measure is important.
.
Substitute x = 40-y
.
44(40-y) + 28y = 1680
1760 -44y +28y = 1680
.
-44y +28y = 1680 -1760
.
-16y = -80
.
y = 5
.
Substitute y =5 to find x.
.
x = 40-y
.
x = 40-5 = 35
.
Check their values to ensure this is the correct answer.
44(35) + 28(5) = 1680 ??
Yes.
.
Answer; 35 44-cent stamps and 5 28-cent stamps.
.
Done.