You spend $20 total on paint and brushes. Paint cost $4 each and brushes cost $0.50 each. You buy twice as many brushes as paint. How many brushes and paint did you buy?
So to solve this problem, you can make a system of equations
\(x = paint \)
\(y = brushes\)
So for the first equation:
Why? Because the total $ of paint and brushes together equals 20, and paints cost 4 dollars and brushes cost 50 cents.
Then for the second equation:
Why? Because the amount of brushes(y), equals twice the number of paints(x).
Then you can use substitution to solve.
\(4x + 0.5(2x) = 20\)
Here I substituted y( as it equals 2x) into the first equation.
\(4x + x = 20\)
\(5x = 20\)
\(x = 4\)
and if you plug it back in:
\(y = 2(4)\)
\(y = 8\)
You have 4 paints and 8 brushes.