Subject
Quantitative Aptitude
Topic
Speed & Distance
How long must a driver take to drive the final 70 miles of a trip if he wants to average 50 miles an hour for the entire trip and during the first part of the trip he drove 50 miles in 1(1/2)hours . ( একজন ড্রাইভার ঘন্টায় গড়ে 50 মাইল বেগে সমস্থ পথ অতিক্রম করতে চাইলে যাত্রা পথের শেষ 70 মাইল যেতে কত সময় লাগবে, যদি সে যাত্রা পথের প্রথম 50 মাইল 1(1/2)ঘন্টায় গিয়ে থাকে। )
How long must a driver take to drive the final 70 miles of a trip if he wants to average 50 miles an hour for the entire trip and during the first part of the trip he drove 50 miles in 1(1/2)hours . ( একজন ড্রাইভার ঘন্টায় গড়ে 50 মাইল বেগে সমস্থ পথ অতিক্রম করতে চাইলে যাত্রা পথের শেষ 70 মাইল যেতে কত সময় লাগবে, যদি সে যাত্রা পথের প্রথম 50 মাইল 1(1/2)ঘন্টায় গিয়ে থাকে। )
ক)
54 minখ)
1 hourগ)
66 minঘ)
70 minExplanation
মোট দূরত্ব = ( 50+70) = 120 মাইল ∴ গড় বেগ ={ মোট দূরত্ব/মোট সময় } বা, মোট সময় = (মোট দূরত্ব/গড় বেগ) = {120 মাইল/ 50 (মাইল/ঘন্টা)} = 12/5 ঘন্টা AB অংশ যেতে মোট সময় লাগে 12/5 ঘন্টা এবং AO অংশ যেতে সময় লাগে (3/2) ঘন্টা । ∴ OB অংশ তথা 70 মাইল যেতে সময় লাগে = {( 12/5 ) - (3/2)} ঘন্টা = {(24-15)/10} = 9/10 ঘন্টা আবার, 1 ঘন্টা = 60 মিনিট ∴ 9/10 ঘন্টা = {(9/10) × 60 } = 54 min .Related questions
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