##### (i) If they run in the same direction.

(ii) If they run in the opposite direction.

a) 3.13 km & 30 km

b) 4.14 km & 40 km

c) 3.33 km & 30 km

d) 4.44 km & 40 km

correct answer is: c) 3.33 km & 30 km

**Explanation**

One bus speed is 40 km/hr

Another bus speed is 50 km/hr

Convert 20 minutes to hours = \frac{20}{60}\ hrs\ or\ \frac{1}{3}\ hrs

We know, Distance = Speed\ \times\ Time

\therefore Distance covered by one bus = \left(40\ \times\ \frac{1}{3}\right) km

\rightarrow\frac{40}{3} km.

And distance covered by another bus = \left(50\ \times\ \frac{1}{3}\right) km

\rightarrow\frac{50}{3} km

So that,

After 20 minutes distance between two buses in the same direction is

= \left(\frac{50}{3}\ -\ \frac{40}{3}\right) km

\rightarrow\frac{50\ -\ 40}{3} km

\rightarrow\frac{10}{3} km or 3.33 km.

After 20 minutes distance between two buses in the opposite direction is

= \left(\frac{50}{3}\ +\ \frac{40}{3}\right) km

\rightarrow\frac{50\ +\ 40}{3} km

\rightarrow\frac{90}{3} km or 30 km.**Ans:** (i) Distance between two buses in the same direction is 3.33 km.

(ii) Distance between two buses in the opposite direction is 30 km.