Supriya runs a marathon race in$50$ minutes at an average speed of $48km/hr$ in order to set a national record she need to win the race in $40$ minutes considering that her speed remain constant at what minimum speed she run to set the record

Step 1. Given data

1. Supriya run the marathon race with the average speed to $48km/hr$
2. Supriya complete the race in $50$ minutes
3. To create record Supriya need to complete race in $40$ minutes

Step 2. Formula used

Speed$=\frac{\mathrm{Distance}}{\mathrm{Time}}$

Step 3. Find the average speed required to create record

Supriya run the marathon race with the average speed to $48km/hr$

Supriya complete the race in $50$ minutes

Average speed$=v=48km/hr$

Time$=t=50$ minutes

Distance$=s$

Speed$=\frac{\mathrm{Distance}}{\mathrm{Time}}$

$$\begin{gathered} \Rightarrow s=vt \\ =\frac{48}{60}\times 50\left[\because 1hr=60min\right] \\ =40km \end{gathered}$$

The average speed to cover $40km$ in $40$ minutes is

Speed$=\frac{\mathrm{Distance}}{\mathrm{Time}}$

$$\begin{gathered} =\frac{40}{40}\times 60\left[\because 1hr=60min\right] \\ =60km/h \end{gathered}$$

Hence the required speed is $60km/h$