A boy runs for 10 minutes at a uniform speed of 18 km per hour. At what speed should he runs for the next 20 minutes so that the average speed becomes 12 km per hour?
Answers
Answered by
0
Answer:
v1 = 18km/hr
t1 = 10min = 10/60 = 1/6hr
t2 = 20min = 20/60 = 1/3hr
distance coverd in first part of journey
s1 = v1*t1 = 18*1/6 = 3km
avg speed = 12km/hr
t = t1+t2
t = 1/6 + 1/3 = 1/2 hr
total distance = v*t = 1/2*12 = 6
distance coverd in second part of the journey
s2 = s - s1
s2 = 6-3 = 3km
v2 = distance/time = s2/t2 = 3/(1/3) = 9 km/hr
HOPE IT HELPS
PLZ MARK ME AS BRAINLIST
Similar questions