Latest Book Aptitude Question SOLUTION: The different between downstream speed and upstream speed is 3 km/h and the total time taken during upstream and downstream is 3 hours. What is the downstream speed, if the downstr

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(#M40165141) BOOK Numerical Ability question boats and stream Keep an EYE

The different between downstream speed and upstream speed is 3 km/h and the total time taken during upstream and downstream is 3 hours. What is the downstream speed, if the downstream and upstream distances are 3 km each?

Asked In Book gayathrri (6 years ago)

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Maya  (4 years ago)

Let Say Speed of Stream = x km/hr

and speed of Rowing = y km/hr

upstream spedd = y - x m/he

Down stream speed = y + x km/Hr

Difference between downstream & upstram speed = 3 km/hr

y + x - (y -x) = 3

=> 2x = 3

x = 3/2 km/Hr

Speed of stream = 3/2 Km/hr

Downstream speed = y +3/2 km/Hr

Upstream speed = y - 3/2 km/hr

Total Time taken = 3/(y +3/2)  + 3/(y-3/2)  = 3

2/(2y +3)  + 2/(2y -3)  = 1

=> 4y - 6 + 4y + 6 = 4y² - 9

=> 4y² - 8y - 9 = 0

=> y = (8 + √64 + 144)/8

=> y = (8 + √208)/8

=> y = (8 + 14.42)/8

=> y = 22.42/8

=> y = 2.8 km/hr

Downstream speed = y +3/2 km/Hr

= 2.8 + 1.5

= 4.3 km/Hr

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