Sagot :
Let X be the cost of 1 notebook and Y be the cost of 1 box of markers.
The presented information gives us the equations:
3X + 2Y = $14.62 (14.62 is the total cost of 15.85 minus the sales tax of 1.23)
Y = 3.95
Plug the value of Y in the second equation into the first equation to get:
3X + 2(3.95) = 14.62
Simplify and solve for X:
3X + 7.9 = 14.62
3X = 6.72
X = 2.24
The cost of each notebook is $2.24
The presented information gives us the equations:
3X + 2Y = $14.62 (14.62 is the total cost of 15.85 minus the sales tax of 1.23)
Y = 3.95
Plug the value of Y in the second equation into the first equation to get:
3X + 2(3.95) = 14.62
Simplify and solve for X:
3X + 7.9 = 14.62
3X = 6.72
X = 2.24
The cost of each notebook is $2.24
Solving for the cost of each notebook?
Step 1: You need a variable to represent the notebooks so let used z. It doesn't matter the letter could be x , y , z.
We have 3 notebooks so, 3z (notebooks) will be used when we set up the equation.
We see 2 boxes of markers @ $3.95 each, so 2( 3.95) is our markers.
Problem: 3z + 2(3.95) = $15.85 amount spent w/ taxes
Step 2: Subtract taxes and discount coupon from total amount spend.
15.85 - 1.23 (w/taxes) = $14.62
14.62 - .75 (coupon used) = $13.87
New equation: (without coupons and taxes)
Multiple 2 x 3.95 markers 3z + 2(3.95)= 13.87
3z+7.90 = 13.87
Subtract:(7.90) form both sides -7.90 -7.90
3z = 5.97
Divide 3 from both sides 3 3
z is cost of each notebook z = $1.99 (cost each notebook)
Check: Multiply 3(1.99) + 2(3.95) + .75(coupon) + 1.23 taxes= $15.85
Add amounts 5.97 + 7.90 + .75 + 1.23 = $15.85
13.87 + .75 + 1.23 = $15.85
14.62 + 1.23 = $15.85
Correct solution both are equal: $15.85 = $15.85
Step 1: You need a variable to represent the notebooks so let used z. It doesn't matter the letter could be x , y , z.
We have 3 notebooks so, 3z (notebooks) will be used when we set up the equation.
We see 2 boxes of markers @ $3.95 each, so 2( 3.95) is our markers.
Problem: 3z + 2(3.95) = $15.85 amount spent w/ taxes
Step 2: Subtract taxes and discount coupon from total amount spend.
15.85 - 1.23 (w/taxes) = $14.62
14.62 - .75 (coupon used) = $13.87
New equation: (without coupons and taxes)
Multiple 2 x 3.95 markers 3z + 2(3.95)= 13.87
3z+7.90 = 13.87
Subtract:(7.90) form both sides -7.90 -7.90
3z = 5.97
Divide 3 from both sides 3 3
z is cost of each notebook z = $1.99 (cost each notebook)
Check: Multiply 3(1.99) + 2(3.95) + .75(coupon) + 1.23 taxes= $15.85
Add amounts 5.97 + 7.90 + .75 + 1.23 = $15.85
13.87 + .75 + 1.23 = $15.85
14.62 + 1.23 = $15.85
Correct solution both are equal: $15.85 = $15.85