Question

To paint his house, Samuel bought 2 cans of paint and one roller for 30$. When friends came over to help, he went back to the store and bought 3 more cans of paint and 2 more rollers for 50$. How much did he pay for each roller?

Answer 1

paint -- p
roller -- r
let's set up a system of equation
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2 can of paint and one roller cost 30 dollar
2p+r=30
3 can of paint and 2 roller cost 50 dollar
3p+2r=50

lets solve that equation
2p+r=30
3p+2r=50

-4p-2r=-60
3p+2r=50
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-p =-10
p =10

2p+r=30
20+r=30
r=10

paint can cost 10 dollar and roller cost 10 dollar as well