What is the volume of the cylinder below?

A fisherman traveled in a boat from point N upstream. After having traveled 6 km, he stopped rowing and 2 hour 40 min after firs

Nat2105 [25]

Answer:

The speed of the river's current is 4.5 km/hr.

Step-by-step explanation:

Given : A fisherman traveled in a boat from point N upstream.

After having traveled 6 km, he stopped rowing and 2 hour 40 min after first leaving N, he was brought back to N by the current.

Knowing that the speed of the boat in still water is 9 km/hour

To find : The speed of the river’s current.

Solution :

Let the speed of current = x km/h

Speed of boat = 9 km/h

Thus, the speed in upstream = (9 - x) km/h

Also, the speed in downstream = x km/h (because the boat is stationary in downstream)

Total distance = 6 km ( from N to the point he reached )

Total time = 2 hours 40 minutes

$\text{2 hours 40 minutes}=2\frac{40}{60}=2 \frac{2}{3} \\\\\text{2 hours 40 minutes}=\frac{8}{3} \text{ hours}$

We know, $\text{Time} = \frac{\text{Distance}}{\text{Speed}}$

According to the question,

$\frac{6}{9-x}+\frac{6}{x}=\frac{8}{3}$

Taking LCM and 6 common

$6[\frac{x+9-x}{(9-x)x}]=\frac{8}{3}$

Take 6 to another side,

$\frac{9}{9x-x^2}=\frac{8}{3\times 6}$

Cross multiply,

$9\times 18=8\times(9x-x^2)$

$162=72x-8x^2$

Taking 4 common and cancel out

$4x^2-36x+81=0$

Solve quadratic equation by middle term split,

$4x^2-18x-18x+81=0$

$2x(2x-9)-9(2x-9)=0$

$(2x-9)(2x-9)=0$

$\Rightarrow 2x-9=0$

$\Rightarrow x=\frac{9}{2}=4.5$

Therefore, The speed of the river's current is 4.5 km/hr.

6 0

3 years ago

I need help on 14 and 15 please help<br> J

Simora [160]

14 is true because all even numbers are multiples of two.

4 0

3 years ago

Read 2 more answers

2. Find the equation of the perpendicular bisector of line PQ where the co-ordinates of P and Q are P (-2, 8) and Q (4,7)

Novosadov [1.4K]

Answer:

2y - 12x = 3

Step-by-step explanation:

gradient of line PQ= (7-8)/ 4+2

-1/6

gradient of perpendicular bisector of line PQ=

-1 ÷ -1/6

-1× -6

6

coordinates of the midpoint of line PQ

(-2+4)/2, (8+7)/2

(1, 15/2)

the perpendicular bisector passes through the midpoint of line PQ

Equation of the perpendicular bisector

y - 15/2 = 6(x - 1)

multiply through by 2

2y - 15 = 12(x - 1)

2y - 15 = 12x - 12

2y - 12x = 3

8 0

2 years ago

A utility bill shows that a household used ed d 2001 gallons of water in a 5 day period. What was the average amount of water us

Paraphin [41]

2001 gallons used in 5 days, so the average for one day is 2001/5=400.2 gallons.

5 0

3 years ago

Read 2 more answers

If one endpoint is (-6,4) and the midpoint is (4,8) what would be the other endpoint ???? if you can explain it would be great

krek1111 [17]

I believe the next one would be 13.2 because if you add 8.4 to -6.4 it gets 4.8 so you just do the same thing

8 0

2 years ago