Tori can carry up to 18 lb in her backpack. her lunch sighs 1 lb, her gym clothes weigh 2 lb and her books weigh 3 lb each. how many books can she carry in her backpack

Her lunch and her gym clothes are 3 lbs combined so that leaves 15 lbs left that she can carry. Do 15/3 and you should get 5.

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.