Answer: Paco bought 7 markers and 8 pencils.
Explanation:
Let's define the variables:
P = number of pencils that Paco bought
M = number of markers that Paco bought.
We know that P + M = 15.
We also know that each pencil costs $0.30 and each marker costs $1.25, and the total price for the whole purchase is $11.15
Then:
P*$0.30 + M*$1.25 = $11.15
Then we have the system of equations:
P + M = 15
P*$0.30 + M*$1.25 = $11.15
To solve this, we can start by isolating one of the variables in the first equation, let's isolate P.
P = 15 - M
Now we can replace this in the second equation to get:
(15 - M)*$0.30 + M*$1.25 = $11.15
$4.50 - M*$0.30 + M*$1.25 = $11.15
$4.50 + M*$0.95 = $11.15
M*$0.95 = $11.15 - $4.50 = $6.65
M = $6.65/$0.95 = 7
Then paco bough 7 markers, and we can find the number of pencisl by the equation:
P + M = 15
P = 15 - M = 15 - 7 = 8
Then Paco bought 7 markers and 8 pencils.