Answer:
37.5 lb
Explanation:
For this question, we have to set up a proportion.
10 lbs of trash over 4 days = 10/4, which, when simplified to be a unit rate (meaning something divided by 1,) is 2.5/1.
Now that we have our unit rate, we can simply multiply that rate by 15 to find the amount of trash Sandra will collect by day 15, which is 37.5 lbs.