Let Kim's age be x. Then Josh's age is (4x+6) The total is x + (4x+1) < 31. Simplify and solve inequality for x 5x + 1 < 31 5x < 31 - 1 = 30 x < 30/5 = 6 ANSWER. Kim is younger than 6 years (1,2, 3, 4 or 5 years old).