notebooks = $5 each
Pack of pens = $3 each
number of notebooks = n
number of pack of pens = p
total items = 97
n + p = 97
total spent on supplies $381
5n + 3p = 381
a)
n + p = 97
5n + 3p = 381
b)
Multiply the first equation by 5
5n + 5p = 485
Then subtract the second equation to eliminate n
5n+5p=485
-
5n+3p=381
__________
0n +2p= 104
p= 104/2
p= 52
Replace p on any equation and solve for n
n+p=97
n + 52 = 97
n= 97-52
n= 45
n=45, p=52
c.
Solve the first equation for n
n+p=97
n= 97-p
Replace n=97-p on the second equation
5n + 3p = 381
5 (97-p) + 3p = 381
Solve for p
485 - 5p + 3p = 381
-2p = 381 - 485
-2p= -104
p= -104/-2
p= 52
Replace p=52 on the first equation and solve for n
n + p= 97
n + 52 = 97
n= 97-52
n= 45
n=45,p=52