Answer:
$42
Explanation:
We must calculate the value of the discount percentage, that is, 30% of 660, like this:
660 * 30% = 198
Now we must subtract that value from the sale price, like this:
660 - 198 = 462
In other words, the surcharge would be:
462 - 420 = 42
The surcharge value would be $ 42