One foot equals 12 inches. Lena's puppy will grow to be at most 28 inches. 28-12=16 inches.
18. 24.5
the possible values of the combined weights of the kittens is not more than 24.5 ounces. Since there are 7 kittens, the combined weight of the kittens is 7w, therefore the above expression could be read as "The combined weight of the kittens is less than 24.5 ounces
There are a lot of combinations so you have to find out ALL the possible combined values. ( I don't think I can fit all of them on here you will probaly have to do some work for it)