The usual price of a stapler sold at Shop X and Y is $40. During a sale, a discount of 20% is given to every stapler sold at Shop X. At Shop Y, a discount of 40% is given to the 4th stapler for every 4 staplers sold. How much cheaper would it be if Joelle buys 11 staplers from Shop X instead of Shop Y?

	Shop X	Shop Y
Price of 1 stapler	80%  $32	100% $40
Every 4th stapler		60% $24

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

Price of 1 stapler from Shop X at 20% discount
= 80% x 40
= ⁸⁰₁₀₀ x 40 
= $32

Cost of 11 staplers from Shop X
= 11 x 32
= $352

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

Cost of 4th stapler at Shop Y
= 60% x 40
= ⁶⁰₁₀₀ x 40 
= $24

Cost of 1 set of 4 staplers at Shop Y
= 40 x 3 + 24
= $144

Number of sets of 4 for staplers at Shop Y
= 11 ÷ 4
= 2 r 3

Cost of 2 sets of 4 staplers at Shop Y
= 2 x 144
= $288

Cost of 3 staplers at Shop Y
= 3 x 24
= $72

Cost of 11 staplers at Shop Y
= 288 + 72
= $360

Amount cheaper if Joelle buys 11 staplers from Shop X instead of Shop Y
= 360 - 352
= $8

Answer(s): $8