A, B and C are on a trip by a car. A drives during the first hour at an average speed of 50 km/hr. B drives during the next 2 hours at an average speed of 48 km/hr. C drives for the next 3 hours at an average speed of 52 km/hr. They reached their destination after exactly 6 hours. Their mean speed was : (A, B ও C তিনজন কার ট্রিপে বের হয় । A প্রথম ঘন্টায় 50 km/hr বেগে, এরপর B দুই ঘন্টা ধরে 48 km/hr বেগে এবং শেষে C তিন ঘন্টা ধরে 52 km/hr বেগে চালায় । 6 ঘন্টায় তারা তাদের গন্তব্যে পৌছে । তাদের গড় গতি কত ছিল?)

A 50 km/hr

B 50(1/3) km/hr 

C 51(1/3) km/hr 

D 52 km/hr

Solution

Correct Answer: Option B

 

মোট দূরত্ব = (50×1) + (48×2)+ (52×3) = 302 km
মোট সময় লাগে = 6 hr 

গড় গতি (mean speed) = (302/6) (km/hr = 50(1/3) km/hr

Practice More Questions on Our App!

Download our app for free and access thousands of MCQ questions with detailed solutions