Walking at 4/5 of her normal speed, a worker is 10 minutes later than usual in reaching her office. The usual time (in minutes) taken by her to cover the distance between her home and her office is Answers: A) 30 B) 35 C) 40 D) 45 E) 50

Rationale: "let v be her normal speed and let t be her normal time . d = ( 4 / 5 ) v * ( t + 10 ) since the distance is the same we can equate this to a regular day which is d = v * t v * t = ( 4 / 5 ) v * ( t + 10 ) t / 5 = 8 t = 40 the answer is c ."
Answer: C