Answer
$\$112.50$
Work Step by Step
Let the cost of $75~lb$ of welding rods be $x$. Then we can write the ratios as:
$\frac{75}{50} $ =$\frac{x}{75}$
By cross multiplication, we get:
$75\times 75=50x$
$5625= 50x$
Divide both sides by $50$ to get $x$ by itself.
$x=112.5$ dollars
