Answer:
The cost of each notebook is $5
The cost of each thumb drive is $18
Explanation:
We solve this problem by the system of equations
Equation for Troy and equation for Lisa and then solve the two
equations simultaneous using the elimination method
Assume that the price of one notebook is $x and the price of one
thumb drive is $y
Troy bought 4 notebooks and 13 thumb drives for $254
∴ 4 x + 13 y = 254 ⇒ (1)
Lisa bought 5 notebooks and 8 thumb drives for $169
∴ 5 x + 8 y = 169 ⇒ (2)
To solve the equation multiply equation (1) by 5 and equation (2) by -4
to eliminate x
∵ 20 x + 65 y = 1270 ⇒ (3)
∵ -20 x - 32 y = -676 ⇒ (4)
Add equations (3) and (4)
∴ 33 y = 594
Divide both sides by 33
∴ y = 18
Substitute the value of y in equation (1) or (2) to find x
∴ 4 x + 13(18) = 254
∴ 4 x + 234 = 254
Subtract 234 from both sides
∴ 4 x = 20
Divide both sides by 4
∴ x = 5
x represents the cost per notebook and y represents the cost per
thumb drive
The cost of each notebook is $5
The cost of each thumb drive is $18