Question

the correct mixture of oil to gas in a weed eater is 1/2 pint of oil to 2 1/2 gallons of gas. how many pints of oil are needed for 10 gallons of gas?

Answer 1

This requires 2 pints of oil.

Using a proportion to solve this, we have:
$\frac{\frac{1}{2}}{2\frac{1}{2}}=\frac{x}{10}$

Cross multiplying, we have
1/2*10 = (2 1/2)*x
5 = (2 1/2)x

Divide both sides by 2 1/2:
5÷(2 1/2) = (2 1/2)x÷(2 1/2)
2 = x

Answer 2

This needs 2 pints of oil.