A MAN ROWS TO A PLACE  48 KMDISTANT AND COMES BACK IN 14HRS.HE FINDS THAT HE CAN ROW 4KM WITH THE STREAM IN THE SAME TIMEAS 3KM AGAINST THE STREAM.WHAT IS THE RATE OF THE STREAM?

Asked by M.s.srinidhi21 | 29th Nov, 2014, 09:32: PM

Expert Answer:

T o t a l space d i s tan c e space c o v e r e d equals 48 space k m T o t a l space t i m e space t a k e n equals 14 space h o u r s space L e t space x space b e space t h e space h o u r s space t h e space m a n space c o v e r e d space i n space 4 space k m space d o w n s t r e a m. S p e e d space d o w n s t r e a m equals open parentheses 4 over x close parentheses space k m divided by h o u r S p e e d space u p s t r e a m equals open parentheses 3 over x close parentheses space k m divided by h o u r F r o m space t h e space g i v e n space s t a t e m e n t comma space w e space h a v e comma fraction numerator 48 over denominator 4 over x end fraction plus fraction numerator 48 over denominator 3 over x end fraction equals 14 rightwards double arrow fraction numerator 48 x over denominator 4 end fraction plus fraction numerator 48 x over denominator 3 end fraction equals 14 rightwards double arrow 12 x plus 16 x equals 14 rightwards double arrow 28 x equals 14 rightwards double arrow x equals 14 over 28 rightwards double arrow x equals 1 half space h o u r D o w n s t r e a m space s p e e d equals fraction numerator 4 over denominator 1 half end fraction equals 8 space k m divided by h o u r U p s t r e a m space s p e e d equals fraction numerator 3 over denominator 1 half end fraction equals 3 space k m divided by h o u r I f space m space i s space t h e space s p e e d space o f space a space b o a t space u p s t r e a m space a n d space n space i s space t h e space s p e e d space o f space t h e space b o a t space d o w n s t r e a m comma space t h e n space s p e e d o f space t h e space c u r r e n t space i s space 1 half open parentheses n minus m close parentheses space k m divided by h r therefore R a t e space o f space t h e space s t r e a m equals 1 half open parentheses 8 minus 6 close parentheses space k m divided by h r equals 1 space k m divided by h o u r

Answered by Vimala Ramamurthy | 30th Nov, 2014, 06:12: PM

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