max asked in Education & ReferenceHomework Help · 8 months ago

# Pratap Puri rowed 22 miles down a river in 2 ​hours, but the return trip took him 5 and one half  hours. ?

Find the rate Pratap can row in still water and find the rate of the current.

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• 8 months ago

Pratap Puri rowed 22 miles down a river in 2 ​hours, but the return trip took him 5 and one half hours. Find the rate Pratap can row in still water and find the rate of the current.

Let the current rate = r mile/hr and Pratap's in still water = p

p+r = 22miles/2hr = 11mph

p-r = 22mile/5.5hr = 4mph

Add the two equations to eliminate r:

2p = 11 + 4 = 15 so p = 7.5mph

r = 11-7.5 = 3.5mph

Pratap can row 7.5mph in still water

The Rate of Current = 3.5mph

• 8 months ago

Let r be the speed in still water

let s be the speed of the current

then 2(x+s) = 22

==> x + s = 11

and 5.5 (x-s) = 22

==> (x-s) = 4

so

==> 2x = 15

==> x = 7.5 mph

from the first equation x+s = 11

==> s = 11-x

==> s = 11 - 7.5

==> s = 3.5 mph