A sweater that originally cost $40 is on sale for 10 percent off. What is the amount of the discount?

$2

$4

$30

$36

X percent = x/100

10 percent = 10/100 = 0.10

10% of $40 = 0.10*40 = 4

You save $4

The old price is $40 and changes to $36 after the discount is applied. This is ignoring any taxes or other surcharges

Anyways I'm going a bit off tangent. The final answer is choice B) $4