Subject
Quantitative Aptitude
Topic
Speed & Distance
A train travels at a speed of 30 km/hr for 12 minutes and at a speed of 45 km/hr for the next 8 minutes. The average speed of the train for this journey is
A train travels at a speed of 30 km/hr for 12 minutes and at a speed of 45 km/hr for the next 8 minutes. The average speed of the train for this journey is
ক)
30 km/hrখ)
36 km/hrগ)
37.5 km/hrঘ)
48 km/hrExplanation
(প্রশ্ন-( একটি ট্রেন 12 মিনিট ধরে 30 km/hr গতিবেগে এবং পরবর্তী 8 মিনিট ধরে 45 km/hr বেগে যাত্রা করে । যাত্রাপথে ট্রেনটির গড় গতিবেগ কত?) 12 min = (12/60) hr = (1/5) hr; 8 min = (8/60) hr = (2/15) hr প্রথমে, 1 hr এ যায় = 30 km ∴ (1/5) hr " " = (1/5)×30 = 6 km পরবর্তীতে, 1 hr এ যায় = 45 km ∴ (2/15) hr " " = (2/15)×45 = 6 km মোট দূরত্ব = (6×6) = 12 km মোট সময় = {(1/5)+(2/15)} = {(3+2)/15} = 5/15 = (1/3) hr গড় বেগ = (মোট দূরত্ব/মোট সময়) = {12/(1/3)} = {12×(3/1)} = 36 km/hrRelated questions
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