Subject
Quantitative Aptitude
Topic
Speed & Distance
A man can reach a certain place in 30 hours. If he reduces his speed by (1/15)th, he goes 10 km less in that time. Find his speed.(একটি লোক কোন স্থানে পৌছাতে 30 ঘন্টা সময় লাগে । যদি সে তাঁর পূর্বের বেগ (1/15) অংশ পরিমাণ কমিয়ে ফেলত তাহলে ঐ সময়ে সে 10 km দূরত্ব কম অতিক্রম করত । তাঁর গতিবেগ কত ?)
A man can reach a certain place in 30 hours. If he reduces his speed by (1/15)th, he goes 10 km less in that time. Find his speed.(একটি লোক কোন স্থানে পৌছাতে 30 ঘন্টা সময় লাগে । যদি সে তাঁর পূর্বের বেগ (1/15) অংশ পরিমাণ কমিয়ে ফেলত তাহলে ঐ সময়ে সে 10 km দূরত্ব কম অতিক্রম করত । তাঁর গতিবেগ কত ?)
ক)
4 km/hrখ)
5 km/hrগ)
5(1/2)km/hrঘ)
6 km/hrExplanation
ধরি, তাঁর গতিবেগ = x তাঁর বেগ কমে = (x/15) ∴ পরবর্তি গতিবেগ = x - (x/15) = (14x/15) প্রথম ক্ষেত্রে, ঐ সময়ে অতিক্রম করে = সময় × বেগ = 30x দ্বিতীয় ক্ষেত্রে, ঐ সময়ে অতিক্রম করে = সময় × বেগ = 30 × (14x/15) শর্তমতে,[ 30x - {(30×14x)/15} ] = 10 => 30x{1-(14/15)} = 10 => 30x {(15-14)/15} = 10 => 30x(1/15) = 10 => 2x = 10 ∴ x = 5Related questions
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