The usual price of a stapler sold at Shop H and J is $20. During a sale, a discount of 20% is given to every stapler sold at Shop H. At Shop J, a discount of 50% is given to the 7th stapler for every 7 staplers sold. How much cheaper would it be if Barbara buys 16 staplers from Shop H instead of Shop J?

	Shop H	Shop J
Price of 1 stapler	80%  $16	100% $20
Every 7th stapler		50% $10

Price of 1 stapler from Shop H in percentage
= 100% - 20%
= 80%

Price of 1 stapler from Shop H at 20% discount
= 80% x 20
= ⁸⁰₁₀₀ x 20 
= $16

Cost of 16 staplers from Shop H
= 16 x 16
= $256

Price of the 7th stapler from Shop J in percentage
= 100% - 50%
= 50%

Cost of 7th stapler at Shop J
= 50% x 20
= ⁵⁰₁₀₀ x 20 
= $10

Cost of 1 set of 7 staplers at Shop J
= 20 x 6 + 10
= $130

Number of sets of 7 for staplers at Shop J
= 16 ÷ 7
= 2 r 2

Cost of 2 sets of 7 staplers at Shop J
= 2 x 130
= $260

Cost of 2 staplers at Shop J
= 2 x 10
= $20

Cost of 16 staplers at Shop J
= 260 + 20
= $280

Amount cheaper if Barbara buys 16 staplers from Shop H instead of Shop J
= 280 - 256
= $24

Answer(s): $24