# To paint his house, Samuel bought 2 cans of paint and one roller for $30. When friends came over to help, he went back to the store and bought three more cans of paint and two more rollers for$50. How much did he pay for a roller?

May 21, 2017

"1 can of paint costs "$10.00 "1 roller costs "$10

#### Explanation:

Let the price of a can of paint be $c$
Let the price of a roller be $r$

Condition 1->2c+1r=$30" ".............Equation(1) Condition 2->3c+2r=$50" "...........Equation(2)
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Multiply everything in $E q u a t i o n \left(1\right)$ by 2 giving:

4c+2r=$60" ".............Equation(1_a) 3c+2r=$50" "...........Equation(2)

$E q u a t i o n \left({1}_{a}\right) - E q u a t i o n \left(2\right)$

c+0=$10=>" 1 can of paint costs "$10.00
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Consider equation(2). I can costs $10 so we have: 3(10)+2r=$50

$30+2r=$50

Subtract $30 from both sides 0+2r=$20

Divide both sides by 2

r=$10 =>" 1 roller costs "$10