Question

A train travels at a speed of 30 km per hour for 12 minutes and then for the next 8 minutes at a speed of 45 km per hour then the average speed for the journey is

• A. 36 km/hr
• B. 37 km/hr
• C. 38 km/hr
• D. 40 km/hr

Answer 1

The correct option is A 36 km/hr

Given train travels 12 minutes with speed 30 km \hr

Then train travels =$\frac{30}{60}\times 12=6km$

And train travels 8 minutes with speed 45 km\ hr

Then train travels =$\frac{45}{60}\times 8=6km$

Then train travels distance in 12+8=20 minutes =6+6=12 km

Then average speed =$\frac{12}{20}\times 60=36$ km \hr