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
Serggg [28]
3 years ago
12

A motorboat travels 172 km in 3 hours going upstream and 372 in 4 hours going downstream. What is the rate of the boat in still

water and what is the rate of the current?
Mathematics
1 answer:
torisob [31]3 years ago
4 0

Answer:

<em>The rate of the boat is 75.17 km/h and the rate of the stream is 17.83 km/h</em>

Step-by-step explanation:

<u>System of Equations</u>

Let's call:

B = speed (rate) of the boat in still water

S = speed (rate) of the stream

The boat travels 172 km in 3 hours when going upstream, that is when the speed of the stream subtracts its own speed. The speed is the distance divided by the time, thus:

\displaystyle B-S=\frac{172}{3}

Multiplying by 3:

3B - 3S = 172        [1]

The boat travels 372 km in 4 hours downstream when the speed of the current adds to its own:

\displaystyle B+S=\frac{372}{4}=93

B + S = 93

Solving for B:

B = 93 - S       [2]

Substituting in [1]

3(93 - S) - 3S = 172

Operating:

279 - 3S - 3S = 172

279 - 6S = 172

Subtracting 279:

- 6S = 172 - 279

- 6S = -107

Multiplying by -1 and solving for S:

S = \frac{107}{6}\approx 17.83\ km/h

From [2]:

B = 93 - \frac{107}{6}

B=\frac{451}{6}\approx 75.17\ km/h

You might be interested in
Feet
ycow [4]
The adult St.Bernard should be around 121 and 198 pounds

Explain:
2.2 x 55 = 121 pounds
2.2 x 90 = 198 pounds
5 0
4 years ago
Hey I need help with 2+2
bulgar [2K]

Answer:

4

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
What is the area, in square centimeters of the trapezoid below?
Katen [24]

Answer:

68.8cm^2

Step-by-step explanation:

A trapezoid=h/2(b1+b2)

A trapezoid=6.4/2(12.9+8.6)

A trapezoid=3.2(21.5)

A trapezoid=68.8cm^2

8 0
3 years ago
If one point on a horizontal line has the coordinates (10, -3), which of the points below are also on the line? Select all that
frozen [14]
The correct answers are:
______________________________________________________
  [B]:  "  (3, -3)  " ;  AND:
______________________________________________________
  [C]:  " (-2, -3) " .
______________________________________________________ 
<u>
Note</u>:
 Any point with the "y-coordinate" of  "-3" would also be on the line.

As such, the correct answers, are:
______________________________________________________
  [B]:  "  (3, -3)  " ;  AND:
______________________________________________________
  [C]:  " (-2, -3) " .
______________________________________________________ 
6 0
4 years ago
If 1 1/2 cups of marshmallows in cups is 1/4 cups of chocolate chip. What’s the number of cups of marshmallows used for 1 cup of
DaniilM [7]
6 cups because 1 1/2 time 4 =6
3 0
3 years ago
Other questions:
  • Jack was getting dressed in the dark and needed to get his socks. There were 18 pairs of socks in the drawer: 8 black pairs, 5 b
    11·2 answers
  • In 1968 it cost $54 000 for a 30-second commercial during the super bowl. In 1973, the cost for a 30-second commercial was $88,0
    9·1 answer
  • Approximately 30,300 citizens of a country died in automobile accidents in 2015. Express this toll in deaths per day
    6·1 answer
  • Evaluate 0.1m + 12n when m=30 and n=1/4
    11·2 answers
  • The amount of a sample remaining after t days is given by the equation P(1) - Al2where A is the initial amount of
    15·1 answer
  • -10 + -5 HEEEEEEEEEELP
    8·2 answers
  • Achilles ordered a pizza with 16 slices. Every hour, he ate half of the remaining slices. Let f(n) be the number of slices Achil
    14·1 answer
  • 9 x 1 + 3 x 1/10 + 4 x 1/1000
    13·1 answer
  • 5. Among 70 students , 40 like tea 24 like coffee and 12 like both drinks then find
    14·1 answer
  • Enter an algebraic expression for the word expression. The quotient of −3 and y
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!