Question

Amith can row a boat d km upstream and the same distance downstream in 5 hours 15 minutes. Also, he can row the boat 2d km upstream in 7 hours. How long will it take to row the same distance 2d km downstream for Amith ?

Answer 1

Hey mate ^_^

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Answer:
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Let the speed of boat and stream be x and y kmph respectively.

According to question,

$\frac{d}{x + y} + \frac{d}{x - y} = 5h \: 15m ---- (1)$

$\frac{2d}{x - y} = 7 ---- (2)$

From eq. (1) and (2)

$\frac{2d}{x + y} = \frac{7}{2}$

Hence,

Amith will take to row 2d km distance downstream in 7/2 hrs.

$= 3.5 hrs$

$= 3 hrs \:30 min$

Therefore,

Answer) 3 hrs 30 min

#Be Brainly❤️

Answer 2

hey

here is answer

Let the speed of boat and stream be x and y kmph respectively.

According to question, 

$\frac{d}{x + y} + \frac{d}{x - y} = 5h \: 15m ---- (1)$

$\frac{2d}{x - y} = 7 ---- (2)$

From eq. (1) and (2)

$\frac{2d}{x + y} = \frac{7}{2}$

Hence, 

Amith will take to row 2d km distance downstream in 7/2 hrs. 

= 3.5 hrs=3.5hrs 

= 3 hrs 30 min



hope it helps

thanks