With number 13, really need assistance.

Acollege is planning to construct a rectangular parking lot on land bordered on one side by a highway. the plan is to use 680 feet of fencing to fence off the other three sides. what dimensions should the lot have if the enclosed area is to be a maximum?

Diana is painting statues she has 7/8 of a liter of paint each statue requires 1/20 of a liter of paint how many statues can she paint?

Which of these is and example of a literal equation? a) 6+30=6^2 b)3x-4y c)12=9+3x d)ax-by=k