Frank brought his girlfriend a sweater that was originally priced at $48 the sweater was marked down 30% frank also has a coupon for an additional 10% off how much did frank save

So, Firstly pick out the important information, in this instance it is;

First price = $48

Discount = 30%

Coupon = 10%

So, 30% of $48

10% = $4.80

20% = 2 x $4.80 = $9.60

30% = $4.80 + $9.60 = $14.40

Plus the 10% of coupon which saves him another $4.80.

so, $48 - $14.40 = $33.60

and then

$33.60 - $4.80 = $28.80

So his final price is $28.80

BUT this is not the question, the question is how much did frank save?

so we can take

$48 - $28.80 which equals to $19.20

This means he is saving $19.20 on his sweater.