Question

one fourth of a journey is covered at a rate of 50 km per hour, 1 3rd 60 kilometre per hour and the rest of the rate of 100 kilometre per hour full stop find the average speed for the whole journey​

Answer 1

Answer:

67.92

Step-by-step explanation:

let total distance be

= L.C.M (4,3 ) = 12 km

dis. covered at 50km/h

= 1/4 * 12 = 3 km

at 60km/h = 1/3* 12 = 4km

at 100km/h = 12 - (3+4) = 5km

total time taken

= 3/50 + 4/60 + 5/100

= 3/50 + 1/15 + 1/20

= (3×6 + 1 × 20 + 15 )/300

=53/300

average speed = 12/53/300

= 3600/53 = 67.92 km/hr