Question

A team can row 40 km in 2 hours when rowing with the current, but only

Answer 1

Answer:  14 km per hour

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Work Shown:

x = rowing speed when there is no current

c = speed of the current

speeds are in km per hour

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Going downstream, i.e. with the current:

x+c = faster speed since the current is pushing you

distance = rate*time

d = r*t

40 = (x+c)*2

x+c = 40/2

x+c = 20

c = 20-x

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Going upstream, i.e. against the current:

x-c = slower speed since the current is working against you

d = r*t

16 = (x-c)*2

16 = 2x-2c

2x-2c = 16

2(x-c) = 16

x-c = 16/2

x-c = 8

x-(20-x) = 8 ... plug in c = 20-x

x-20+x = 8

2x-20 = 8

2x = 8+20

2x = 28

x = 28/2

x = 14 km per hour is the rowing speed when there is no current

Side note: the speed of the current is c = 20-x = 20-14 = 6 km per hour.