Question

A boat travels 4 km in 10 minutes with
the current and 1 km in 15 minutes
against the current. Determine the
speed of the boat.​

Answer 1

=4km/hr=0.0668km/min

b=1km/min

e=a−c=0.0668km/min

b=a+c=1km/min

b+e=a+a−c+c=2a=1+0.668=1.0668

a=0.0834km/min

t=da=15/0.0834≈180minutes=3hours

Answer 2

Solution

Given :-

• boat travels 4 km in 10 minutes with
• the current
• 1 km in 15 minutes against the current

Find :-

• Speed of boat

Explanation

Let,

• Speed of boat = x
• Speed of stream = y

We Know,

$\boxed{\tt{\red{\:Speed\:=\:\dfrac{Distance}{Time}}}}$

$\boxed{\tt{\green{\:1km\:=\:1000m}}}$

So,

• 4 km = 4000 m

Then,

==> Speed of current = 4000/10

==> Speed of current = 400 m/min

According to question

==> x + y = 400__________________(1)

And,

• 1 km = 1000 m

Then,

==> Speed against current = 1000/15

==> Speed against current = 200/3 m/min

According to question

==> x - y = 200/3________________(2)

Add equ(1) & equ(2)

==> 2x = 400 + 200/3

==> 2x = (400×3 + 200)/3

==> 2x = (1200+200)/3

==> 2x = 1400/3

==> x = 1400/(3×2)

==> x = 700/3

Hence

• Speed of boat = 700/3 m/min.

____________________