Mathematics, 03.07.2019 17:30 alexandriacatro9419

The speed of a stream is 4 mph. a boat travels 8 miles upstream in the same time it takes to travel 16 miles downstream. what is the speed of the boat in still water

Answers: 2

Show answers

Answers

Answer from: queen582

The speed of the stream = 4 mph.

Let us assume speed of the boat in still water = x mph.

Total speed upstream = (x-4) mph.

Total speed downstream = (x+4) mph.

We know, time, speed and distance relation.

Time = Distance / Speed.

Total time taken upstream = 8 / (x-4)

Total time taken downstream = 16/(x+4).

Time taken upstream = time taken downstream.

Therefore,

8 / (x-4) = 16/(x+4).

On cross multiplication, we get

16(x-4) = 8(x+4).

16x - 64 = 8x +32.

Adding 64 on both sides, we get

16x - 64+64 = 8x +32+64

16x = 8x + 96.

Subtracting 8x from both sides, we get

16x-8x = 8x-8x + 96.

8x = 96.

Dividing both sides by 8, we get

x = 12.

Therefore, 12 mph is the speed of the boat in still water.

Answer from: gabrielolivas59

Answer

Find out the speed of the boat in still water .

To proof

Let us assume that the speed of the boat in still water be u .

As given

The speed of a stream is 4 mph

hence

speed upstream = u - 4

speed downstream = u + 4

Formula

$Time = \frac{Distance}{speed}$

As given

A boat travels 8 miles upstream in the same time it takes to travel 16 miles downstream.

First case for the upstream

$Time = \frac{8}{u - 4}$

Second case for the downstream

$Time = \frac{16}{4 + u}$

now compare the equations

$\frac{8}{u - 4} = \frac{16}{u + 4}$

simplify the equation

8( u +4 ) = 16 (u -4)

8u +32 = 16u - 64

8u = 96

$u = \frac{96}{8}$

u = 12 mph is the speed of the boat in still water .

Hence proved

Answer from: Quest

Where’s the problems ? ?

Answer from: Quest

the correct option is 2.

step-by-step explanation:

according to the given information triangle abc is a right angle triangle with right angle at a. segment ab is 5 and segment ac is 7. point d is on segment bc and angles adb and adc are right angles.

it is given that triangles abd, cad, and cba are similar.

two triangles are similar if their corresponding sides are proportional.

in triangle cba, using pythagoras theorem

$ab^2+ac^2=bc^2$

$ab^2+ac^2=x^2$ )

triangle abd and cba are similar,

$\frac{ab}{bc}=\frac{bd}{ab}$

$ab^2=bc\cdot bd$

$25=bc\cdot bd$ (2)

triangle cad and cba are similar,

$\frac{ac}{bc}=\frac{cd}{ac}$

$ac^2=bc\cdot dc$

$7\times 7=bc\cdot dc$

$49=bc\cdot dc$ )

using (1), (2) and (3), we get

$25+49=x^2$

$74=x^2$

hence proved.

therefore option 2 is correct.

Another question on Mathematics

Mathematics, 21.06.2019 14:10

What is the perimeter, p, of a rectangle that has a length of x + 8 and a width of y − 1? p = 2x + 2y + 18 p = 2x + 2y + 14 p = x + y − 9 p = x + y + 7

Answers: 3

Answer

Mathematics, 21.06.2019 23:30

What is the gcf of 20c^3-5c^4+30c^6

Answers: 2

Answer

Mathematics, 22.06.2019 00:30

Will mark brainliest for correct answer! i have been on this problem for an hour and can't find the answer. i'm begging here! incase you cant read the instructions in the picture because of too much or too little lighting: note: enter your answer and show all the steps that you use to solve this problem in the space provided.write a list of steps that are needed to find the measure of b. provide all steps as clear as possible, !

Answers: 1

Answer

Mathematics, 22.06.2019 01:10

If the probability of an event happening is 65% then the probability this event does not occur?

Answers: 1

Answer

You know the right answer?

The speed of a stream is 4 mph. a boat travels 8 miles upstream in the same time it takes to travel...

Questions