Question

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Upstream speed of boat and stream speed are in the ratio 2: 1 respectively and the difference between downstream speed and speed of boat in still water is 9 km/hr.
If speed of boat is increased by 4 km/hr, then what is the approximate time taken by boat to cover 324 km downstream?
61 hours​

Answer 1

Answer:

8.1hr

Step-by-step explanation:

upstream speed=b-s

b =speed of boat

s=speed of stream

u=upstream speed

d=(downstream speed

(b-s)/s=2/1. 1

d-b=9

b+s-b=9

s=9kmph

f=final speed of boat=b+4

from equation 1

b-s=2s

b=3s=3*9=27

d=f+s

=27+4+9=40kmph

324/t=40

t=324/40=8.1hr

Check the correct ans is 8.1hr