Direct Variation word problem help

Question

the water pressure on a scuba diver is directly proportional to the depth of the diver. If the pressure on a diver is 22.5 psi when she is 50 feet below the surface, how far below the surface will she be when the pressure is 36 psi?

Answer 1

d represents depth

 

22.5 : 50 :: 36: d               direct proportion

22.5d = 50(36)                  product of means/extremes

22.5d = 1800                    simplify

d = 80                               divide both sides by 22.5