Points P and Q are 400 km apart. A person starts from P towards Q at 6 a.m. at a speed of 20 km/h. Another person starts from Q towards Pat 6 : 30 a.m. at a speed of 30 km/h. At what time will they meet?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 2 : 18 p.m.
Distance = Speed × time
Relative speed in opposite direction = S1 + S2
Distance between P and Q = 400km
Speed of first-person = 20km/h
Speed of the second person = 30 km/h
So, distance covered by the first person in 30 min = 20 × 30/60 = 10 km
Now both person running towards each other at 6 : 30 am
distance between them = 400 - 10 = 390
Time = 390/(20 + 30) = 39/5 hours
= 7 hours 48 min
So, they meet = 6 : 30 am + 7 hours 48 min = 2 : 18 pm