Manoj travelled one third of a distance at an average speed of 16 km/hr then half of distance at a speed of 15Km/hr and covered the rest of distance at an average speed of 20km/hr. If he took total of 15 hours in completing the journey then total distance covered by him is?
a) 205 Km
b) 190 Km
c) 240 Km
d) 250 Km
Let's take total distance travelled in parts are 6 We have to find here Average Speed = Total distance travelled / Total time taken Total distance travelled in parts are 6 Total time taken = distance_1/speed_1 + .... 1st one is 1/3rd of distance which is 1/3rd of 6 = 2 at speed of 16km/h 2nd one is 1/2 of distance which is 1/2 of 6 = 3 at speed of 15km/h Average Speed = 6/ (2/16 + 3/15 + 1/20) = (6/15)*40 We have Average Speed now & total time also A.T.Q = 15 hours So Total distance = Average Speed * Total time = (6/15)*40 * 15 = 6*40*15/15 = 6*40 = 240 Km Ans = 240 Km