the heaviest backpack juan can carry safely weighs 15 pounds. his notebook weighs 4 pounds. if his books average 3.5 pounds, how many books can he carry? l

The answer would be 3 because 15-4=11, each book is 3.5 pounds

3.5+3.5=7

7+3.5=10.5

If he can only weigh 15 pounds and he already has 4 you have to add 3.5 plus 3.5 that makes 7 plus 4 is 11 you can add one more so then you would have 14.5 and that would be enough