Two girls start from the same place, walk at the rate of $4 \mathrm{km}$ per hour and $4.5 \mathrm{km}$ per hour respectively. How many kilometres will they be apart at the end of $3\frac{1}{2}$ hours, if they walk in the opposite direction?

Gopal covers $100 \mathrm{km}$. He travels at a speed of $60 \mathrm{kmph}$ for the first $40 \mathrm{km}$ and the rest of the distance at $40 \mathrm{kmph}$. What is his average speed in $kmph$?

1. $44.20$
2. $45.20$
3. $46.20$
4. $47.20$

Ali travels a distance of $300 \mathrm{m}$ in $2$ minutes and $30$ seconds. What is his speed in $\mathrm{kmph}$?

A man covers a certain distance in 10 minutes with the speed of 15km/hr. If he wants to cover the same distance in 7 minutes, then what should be his speed?