Lela is buying spools of yarn for a knitting class. she can buy a 40-yard spool for 15.60 or a 60 yard spool for 19.20. which is the better buy? explain

For the 40-yard pool, you divide 15.60 by 40 (should be a decimal.) 0.39 which would mean that every yard is worth 0.39 cents.
For the 60 yard pool, same basic concept. 19.20 divided by 60. Each yard would be 0.32 cents.
The 60 yard pool would be better because it is a cheaper price for the yardage. If you take the 0.39 from the first pool and multiply it by 60, you would get 23.40. therefore, Lela is saving money.