1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
geniusboy [140]
3 years ago
10

a tourist boat is used for sightseeing in a nearby river. The boat travels 2.4 miles downstream and in the same amount of time.

it travels 1.8 miles upstream, if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river. show me the work
Mathematics
1 answer:
Gemiola [76]3 years ago
8 0

Answer:

The current of the river has a speed of 3 miles per hour

Step-by-step explanation:

Let's call v the speed of the boat in calm waters.

We know that:

v = \frac{d}{t}

Where d is the distance in miles and t is the time

When the boat travels down we have to:

d=2.4\ miles

If s is the speed at which the boat travels downstream and c is the speed of the river then

s=(v+c)

And

t=\frac{d}{s}\\\\t=\frac{d}{v+c}\\\\t=\frac{2.4}{21+c}

When the boat travels upstream we have to:

d=1.8\ miles

s=(v-c)

t=\frac{d}{s}\\\\t=\frac{d}{v-c}\\\\t=\frac{1.8}{21-c}

We know that the time he navigate upstream is the same time he navigate downstream

Then:

\frac{2.4}{21+c}=\frac{1.8}{21-c}

We solve the equation for c

2.4*(21-c)=(21+c)*1.8

50.4-2.4c=37.8+1.8c

50.4-37.8=1.8c+2.4c

4.2c=12.6

c=\frac{12.6}{4.2}

c=3\ miles\ per\ hour

You might be interested in
Which expression is the equivalent
Gwar [14]
I think you are correct 
7 0
3 years ago
What is f=kry, for y
geniusboy [140]
F = kry

f/kr = y

y = f/kr

Answer: y = f/kr

*Hope that helps and enjoy Brainly:)
7 0
3 years ago
If m 1=55, what is m 5?
AleksAgata [21]
275 if i'm not mistaken
6 0
3 years ago
Read 2 more answers
How is the pattern changing to get from one term to the next? 55, 49, 43, 37, 31,...
ZanzabumX [31]

Answer:

C.

Step-by-step explanation:

55-6=49

49-6=43

43-6=37

etc.

6 0
3 years ago
the sum of three numbers is 90. the third number is 4 times the first. the second number is 6 less than the first. what are the
igor_vitrenko [27]

Answer: 16, 10, 64

Step-by-step explanation:

64/4=16, so the 3rd number is 4x the first.

16-6=10. 6 less than the first number.

16+10+64=90.

4 0
2 years ago
Other questions:
  • Find the center of the circle whose equation is (x - 8) 2 + (y + 2) 2 = 64.
    12·2 answers
  • mplete the work to solve for y: 2 5 ( 1 2 y + 5 ) − 4 5 = 1 2 y − 1 + 1 10 y 1.Distributive property: 1 5 y + 2 − 4 5 = 1 2 y −
    7·2 answers
  • Two cats, Tom and Bob, caught together 42 mice in three days. Each day, Tom caught twice as many mice as in the previous day, wh
    14·1 answer
  • What strategy do you most commonly use to identify a pattern
    9·2 answers
  • What is the sum 3/5 3/7
    6·1 answer
  • Simplify: Square root of 8xy squared
    6·1 answer
  • -Solve the system of equations.<br>- 10y + 9x = -9<br>10y + 5x = -5​
    14·2 answers
  • Please help me with this
    13·2 answers
  • An adult takes 400 mg of ibuprofen. Two hours later, there is 201.6 mg of
    6·1 answer
  • 15
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!