Answer:
$325
Step-by-step explanation:
Net pay is the gross pay minus all the deductions.
400-24.80-5.20-45 = 325
Take the discount. Let's call it x%. Turn it into a fraction, and multiply it by the item. Let's call the item "i".
The amount discounted is

.
Now subtract this from the original cost of the item.
Therefore,

is the solution.
6 x 7 = 42
And the missing number is 8, because 7 x 8 = 56.