Time and Distance Problems and Solutions

• 22. The distance between two cities A and B is 330 Km. A train starts from A at 8 a.m. and travel towards B at 60 km/hr. Another train starts from B at 9 a.m and travels towards A at 75 Km/hr. At what time do they meet?

  1. 10 am
  2. 11 am
  3. 12 pm
  4. 1 pm

  Answer :

  Option B

  Explanation:

  Suppose they meet x hrs after 8 a.m.
  then
  (Distance moved by first in x hrs) + [Distance moved by second in (x-1) hrs]
  = 330
  So, 60x+75(x-1) = 330
  
  x=3.
  
  So,they meet at (8+3). i.e 11a.m.

• 23. A man is walking at the rate of 5 km/hr crosses a bridge in 15 minutes. The length of the bridge is

  1. 1000 meters
  2. 1050 meters
  3. 1200 meters
  4. 1250 meters

  Answer :

  Option D

  Explanation:

  We need to get the answer in meters. So we will first of change distance from km/hour to meter/sec by multiplying it with 5/18 and also change 15 minutes to seconds by multiplying it with 60.
  
  \begin{aligned}
  Speed = 5* \frac{5}{18} = \frac{25}{18}m/sec \\
  Time = 15*60 seconds = 900 seconds \\
  
  Distance = Time * Speed \\
  Distance = \frac{25}{18}*900 = 1250 meter
  \end{aligned}