Cant figure out the problem

Liesl grew 7/12 of a foot in one year. her little sister grew 1/3 of a foot during that same year. how much more did liesl grow than her little sister did

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

Miss henderson wants to build a fence around a rectangular garden in her backyard in the scale drawing the perimeter of the garden is 14 in of the actual length of a b is 20 ft how many feet of fencing what you need