One-third of a certain journey was covered at the speed of 20 km/hr, one-fourth at 30 km/hr and the rest at… · ABC26GN3577
Subject: General Aptitude · Chapter: Time and Distance · Exam: A.A.O. Exam. 2009
One-third of a certain journey was covered at the speed of 20 km/hr, one-fourth at 30 km/hr and the rest at the speed of 50 km/hr. Find the average speed per hour for the whole journey.
Answer
No answer key was printed for this question.
Explanation
Let the total distance be x km. Then, x x Distance covered at 20 km/hr = km; Distance covered at 30 km/hr = km; 3 4 x x 5x Distance covered at 50 km/hr = x – + km = km. 3 4 12 ( x/3) ( x/4) (5 x/12) Total time taken = + + hrs 20 30 50 x x x 4x x = + + hrs = hrs = hrs. 60 120 120 120 30 30 \ Average speed for the whole journey = x × km/hr = 30 km/hr. x
Explanation as extracted from the printed page; notation may be imperfect.