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 40% is given to the 4th stapler for every 4 staplers sold. How much cheaper would it be if Barbara buys 10 staplers from Shop H instead of Shop J?

	Shop H	Shop J
Price of 1 stapler	80%  $16	100% $20
Every 4th stapler		60% $12

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 10 staplers from Shop H
= 10 x 16
= $160

Price of the 4th stapler from Shop J in percentage
= 100% - 40%
= 60%

Cost of 4th stapler at Shop J
= 60% x 20
= ⁶⁰₁₀₀ x 20 
= $12

Cost of 1 set of 4 staplers at Shop J
= 20 x 3 + 12
= $72

Number of sets of 4 for staplers at Shop J
= 10 ÷ 4
= 2 r 2

Cost of 2 sets of 4 staplers at Shop J
= 2 x 72
= $144

Cost of 2 staplers at Shop J
= 2 x 12
= $24

Cost of 10 staplers at Shop J
= 144 + 24
= $168

Amount cheaper if Barbara buys 10 staplers from Shop H instead of Shop J
= 168 - 160
= $8

Answer(s): $8