Answer:
$24.36 for the bookbag if they tax the original price
$23.97 if they tax the sales price
$31.10 for the necklace if they tax the original price
$30.60 if they tax the sales price
So an overall of $55.46 was spent for a taxing of the original price and an overall of $54.57 was spent for the taxing of the sales price.
Explanation:
20% of $28.00 is $6.60, subtract $6.60 from $28.00 and you'll get $22.40.
7% of $28.00 is $1.96, add $1.96 to $22.40 and you'll get $24.36 (for taxing of the original price). If you want the taxing of the sales price then you'd do 7% of 22.40 which is $1.57, add that to $22.40 and you get $23.97
Then you do the same for the necklace:
20% of $35.75 is $7.15, subtract $7.15 from $35.75 and you'll get $28.60.
7% of $35.75 is $2.50, add $2.50 to $28.60 and you'll get $31.10 (for taxing of the original price). If you want the taxing of the sales price then you'd do 7% of 28.60 which is $2.00, add that to $28.60 and you get $30.60
Add the final numbers and you'll get your overall.
Hope this helps