a boy run for 20 min At a uniform speed of 18 km/hr.At what speed should he run of the next 40 min so that the average speeds come 24 km/hr
Answers
Answered by
1
very simple
average speed = d/t
d=s*t
1 part s=5m/s
t=20min
2part s=x
t=40 min
distance travelled by both is 5*20+x*40=100+40x
time taken by both is 60 min
a.s=24*5/18=20/3m/s
20/3=100+40x/time taken=60
120=3(100+40x)
120=300+120x
120x=180
x=1.5m/s
speed is 1.5m/s or5.4 km/h
average speed = d/t
d=s*t
1 part s=5m/s
t=20min
2part s=x
t=40 min
distance travelled by both is 5*20+x*40=100+40x
time taken by both is 60 min
a.s=24*5/18=20/3m/s
20/3=100+40x/time taken=60
120=3(100+40x)
120=300+120x
120x=180
x=1.5m/s
speed is 1.5m/s or5.4 km/h
Similar questions