Two friends, kelly and beth, are growing out their hair. they plan to cut it off at a certain point and donate it to a charity that makes wigs for people with cancer. kelly's hair is already 29 centimeters long and grows at a constant rate of 1 centimeter per month. beth's hair is 13 centimeters and growing at a speed of 3 centimeters per month. if the girls get their hair cut on a certain day, they will have exactly the same length to donate. how long will their hair be? How long will that take?
