Question

Distance between two towns P and Q is
240 km. A motor cycle rider starts from P
towards Q at 8 pm at a speed of 40 km/h.
At the same time another motor cycle ride
starts from Q towards P at 50 km/h. At
what time will they meet?
(a) 9:45 pm
(b) 10:40 pm
(c) 11 pm
(d) 10:30 pm​

Answer 1

Step-by-step explanation:

Question says that, Two towns named P and Q having distance of 240km. a cycle rider starts from town P at 8pm with a speed of 40km/hr. At the same time another cycle rider starts from town Q towards P with a speed of 50km/hr.

Step 1 : Finding their relative speed :

When two bodies moving towards themselves is called as ‘relative speed’

Relative speed is given by :

→ Sum of the speed of the two bodies.

→ (40 + 50)km/hr

→ 90km/hr

Step 2 : Finding the time of their meeting :

Since, they are approaching each other.

Time taken = $\sf \dfrac{Distance}{Relative \: speed}$

• Distance = 240km (given)
• Relative speed = 90km/hr

So,

Time taken = $\sf \dfrac{240}{90}$

→ $\sf \dfrac{8}{3}hrs$

Convert it into minutes :

Since, 1hr = 60 min

Therefore,

→ $\sf \dfrac{8}{3} \times 60$

→ 8 × 20

→ 160minutes.

The started at 8pm

And they meets after 160 minutes or,

2hrs and 40minutes.

So, the time they will meet each other at :

→ 8:00 + 2:40

→ 10:40p.m.