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
ki77a [65]
3 years ago
8

Bob can row 12 mph in still water. The total time to travel downstream and return upstream to the starting point is 4 hours. If

the total distance downstream and back is 36 miles, determine the speed of the river (current speed).
Mathematics
1 answer:
RSB [31]3 years ago
6 0

Answer:

\boxed{\sf \ 6 \ mph \ }

Step-by-step explanation:

when Bob travels downstream his speed is 12 + x

where x is the speed of the river

he travels 36/2 = 18 miles

it takes

   \dfrac{18}{(12+x)}

hours to  do it  

when Bob travels upstream his speed is 12 - x

it takes

   \dfrac{18}{(12-x)}

hours to  do it  

finally, it takes

   \dfrac{18}{(12+x)}+\dfrac{18}{(12-x)}=4

18(12-x+12+x)=4(12+x)(12-x)\\\\ 18*24=4(12^2-x^2)\\ 4x^2=576-432=144\\ 2x=12\\  x = 6

So the current speed is 6mph

it takes 1 hour to downstream and 3 hours to upstream

hope this helps

You might be interested in
What is the exact distance between the point (-2,-1) and the point (6,8)
RUDIKE [14]
The answer is B. Use distance formula...

d =  \sqrt{(6 + 2) {}^{2}  + (8 + 1) {}^{2} }
6 0
3 years ago
Read 2 more answers
A container can hold quarts of 8 3/5cooking oil. It contains 1 1/3 quarts of cooking oil. How much more cooking oil is needed to
Mamont248 [21]

Answer:

4 14/15

Step-by-step explanation:

8 3/5 - 11/3

8 9/15 - 55/15

8 9/15 - 3 10/15

7 24/15 - 3 10/15

4 14/15

6 0
3 years ago
The altitude of a plane is 1200 meters. From a point on the ground, the angle of elevation of an airplane is 25º. What is the di
gtnhenbr [62]

Answer:

2839.4 meters

Step-by-step explanation:

Given that:

Altitude = 1200 m

Using trigonometry :

The distance from point P to the airplane :

Using trigonometric relation :

Sin θ = opposite / hypotenus

Sin θ = altitude / x

Sin θ = 1200 m / x

Sin 25 = 1200 / x

0.4226182 = 1200 / x

x = 1200 / 0.4226182

x = 2839.4423

Distance from P to airplane = 2839.4 meters

8 0
3 years ago
Which equation represents a linear function?<br> Select two answers.
Deffense [45]
Equations that represents a linear function are Answers A and D
5 0
2 years ago
Which sampling method is generally considered the weakest?
babunello [35]
Answer – C. (Convenience sampling)

The sampling method that is generally considered the weakest is convenience sampling. This is because in convenience sampling, there is usually no inclusion criteria identified prior to the selection of subjects. Convenience sampling involves getting participants wherever you can conveniently find them. Typically, the first available participants (or any other primary data source, as the case may be) will be used for the research without any additional requirements.Other names by which convenience sampling is known are: Incidental Sampling, Chunk Sampling, and Accidental Sampling.
8 0
3 years ago
Read 2 more answers
Other questions:
  • A rectangular prism has a length of 2 cm, a width of 4 cm, and a volume of 64 cubic cm. Find the height:
    15·1 answer
  • What is the least common multiple of 6 and 8?
    11·2 answers
  • ASAP! I NEED THIS DONE AS QUICKLY AS POSSIBLE WITH WORKING OUT
    10·1 answer
  • I like division show me the work 5 go into. 5÷274
    15·1 answer
  • Help! Thanks!!!!!!!!!!!
    9·1 answer
  • Brian skied for 0.75 hours at an average speed of 9.25 miles per hour. His sister Tori calculated the distance Brian skied. Tori
    13·2 answers
  • I need help I’ll give brainliest
    12·1 answer
  • can anyone help me with this slope-length activity? whoever answers will get 5 stars and brainliest, i know its a bit of work so
    7·1 answer
  • For the polyhedron, use Euler's Formula to find the missing number.
    10·1 answer
  • _ x 2 + 1 = 25<br><br> Pls help I need the answer
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!