Answer:
You save $0.008 Â per load if you buy the 15-pound box.
Step-by-step explanation:
IN 5 POUND BOX
Here, 5 pound box can wash 20 loads
Also, 5 pound box costs $3.50
⇒ The cost of doing 20 loads  = $3.50
⇒ The cost of 1 load  = [tex]\frac{3.50}{20} = 0. 175[/tex]
So, the cost of laundering 1 load here  =  $0.175
IN 15 POUND BOX
Here, 15 ( = 5 x 3) Â pound box can wash 20 x 3 Â = 60 Â loads
Also, 15 pound box costs $10.00
⇒ The cost of doing 60 loads  = $10.00
⇒ The cost of 1 load  = [tex]\frac{10}{60} = 0. 167[/tex]
So, the cost of laundering 1 load here  =  $0.167
Now, Savings  = Cost per load in 5 pound box - Cost of 1 load in 15 pound
= $0.175 Â - $0.167
= $0.008
Hence, you save $0.008 Â per load if you buy the 15-pound box.