Question

A train running at 75 km/hr crosses another train running at 30 km/hr in the same direction in 108 seconds. If the length of the fast-moving train is 950 m, then what is the length (in m) of the slow-moving train?

• A. 400
• B. 450
• C. 350
• D. 300

Answer 1

Answer:

A. 400

Since the trains are moving in the same direction, we use relative speed

Step 1: Relative Speed

$75 - 30 = 45 \text{ km/hr}$

Convert km/hr to m/s:

$45 \times \frac{5}{18} = 12.5 \text{ m/s}$

Step 2: Use Distance = Speed × Time

Time = 108 seconds

$\text{Total length of both trains} = 12.5 \times 108$
$= 1350 \text{ m}$
Step 3: Find length of slow train

$\text{Length of slow train} = 1350 - 950$
$= 400 \text{ m}$

Length of the slow-moving train = 400 m