Question

Supriya runs a marathon race in 50 minutes at an
average speed of 48 km/hour. In order to set a national
record, she needs to win the race in 40 minutes.
Considering that her speed remains constant, at what
minimum speed should she run to set the record?
​

Answer 1

Step-by-step explanation:

speed1=48km/hr and time1=50/60hr

distance=speed*time

distance=48*50/60=40km

now it is given that the distance remains same but she has to win the race in 40 min

therefore now:

time2=40/60 hr and distance=40km

speed2=40/(40/60)=40*60/40=60 km/hr

ans: (b) 60km/hr