An advertisement claims that a 5-pound box of detergent will wash 20 loads of laundry. a 5-pound box costs $3.50. a 15-pound box costs $10.00. about how much will you save per load if you buy the 15-pound box?

With the 15 pound box you can wash 3x the amount of laundry for 30 cents less .

Step-by-step explanation:

$3.50 x3 will do the same amount of laundry but will cost more.

so your better buy would be the 15 pound box. :]