Answer:
5 books
Explanation:
Given that Toni carries upto 18 lbs in her backpack.
The maximum weight Toni can carry is 18 lbs.
Of these 18 lbs, already lunch of 1 lb and gym clothes of 2 lbs are included.
hence available for books is only the remaining 15 lbs.
Total weight in backpack= 18 lbs(Maximum)
Weight of lunch = 1 lb
Weight of her gym clothes = 2 lb
Hence maximum weight available for books = 18-(1+2) = 15 lbs
Weight of one book = 3 lbs.
No of books she can carry = 15/3 = 5 books