Sunland Company recently performed repair services for a customer that totaled $$680.$ Somehow the bill was lost and the company accountant was trying to recreate the bill from memory. This is what was remembered:

Total bill

$$680$

Labor profit margin $10$

Materials profit margin

$20\%$

Total labor charges $$470$

Cost of materials

used

$$120$

Total hourly cost $$22\mathrm{.}5$

What was the material loading $\%$ used?

$20\%$

$75\%$

$40\%$

$90\%$