A man swimming in a stream which flows (3/2) km/hr finds that in a given time he can swim twice as far with the stream as he can against it. At what rate does he swim?
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
ক ((9/2) km/hr)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
Let the rate of his swim x km/h
When he swim with the flow then speed =(x + 3/2) km/h
∴ S1 = (x + 3/2) × t
When he swim against the flow stream then speed = (x - 3/2) km/h
∴ S2 = (x - 32) × t
According to the question,
S1 = 2S2
⇒ (x + 3/2)t = 2(x - 3/2)t
⇒ (2x + 3)/2 = 2x - 3
⇒ 2x + 3 = 4x - 6
⇒ 9 = 2x
⇒ x = 9/2 km/hr
