Mathematics College

A boat travels 50 miles downstream in 2 hours and it takes 5 hours to travel back upstream. What is the speed of the boat if it were in still water and what is the speed of the river current?

Answers

Answer 1

The 50 mile distance traveled downstream and back that takes 2 hours and 5 hours respectively gives;

The speed of the boat in still water = 17.5 mph

The river current flows at 7.5 mph

How can the boat speed be calculated?

Let v represent the speed of the boat and let u represent the speed of the river current.

Distance the boat travels downstream = 50 miles

Time taken to travel downstream by the boat = 2 hours

Time taken to travel back upstream = 5 hours

[tex]velocity = \frac{distance}{time} [/tex]

Therefore;

Which gives;

[tex]v + u = \frac{50}{2} = 25...(1)[/tex]

v + u = 25

[tex]v - u = \frac{50}{5} = 10...(2)[/tex]

v - u = 10

Adding equation (1) to equation (2) gives;

(v + u) + (v - u) = 2•v = 25 + 10 = 35

2•v = 35

v = 35 ÷ 2 = 17.5

The speed of the boat, v = 17.5 mph

u = 25 - v

Which gives;

u = 25 - 17.5 = 7.5

The speed of the river current, u = 7.5 mph (downstream)

Learn more about equations of motion here:

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Related Questions

guys pls help me pls

Answers

Answer:

[tex]77 {m}^{2} [/tex]

Step-by-step explanation:

Given,

Height of the parallelogram = 7m

Base of the parallelogram = 11 m

Therefore, area of the parallelogram = b × h

= 7m × 11m

[tex]77 {m}^{2} (ans)[/tex]

The weights of newborn babies are distributed normally, with a mean of approximately 105 Oz and a standard deviation of 15 Oz. If a newborn baby is selected at random. What if the probably that the baby weighs less than 150 Oz? help please!! Also I need to round answer to nearest thousandth

Answers

Answer:

0.999 = 99.9% probability that the baby weighs less than 150 Oz.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

The weights of newborn babies are distributed normally, with a mean of approximately 105 Oz and a standard deviation of 15 Oz.

This means that [tex]\mu = 105, \sigma = 15[/tex]

What if the probabability that the baby weighs less than 150 Oz?

This is the pvalue of Z when X = 150. SO

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

so for this, all we have to do is add %50 of the first score to the second one, first lets find out what %50 of that score is

%50 of 60 = 30 (because %50 is half of something)

next, we add that new amount to the first score

60 + 30 = 90

so 90 is %50 more then 60, or 90 is %150 of 60

Logan is a land surveyor. He wants to determine d, the distance across a lake that cannot be directly measured. He draws this diagram to help him.

A right triangle with side length 7 kilometers, d, and hypotenuse of 9 kilometers.

What is the approximate distance across the lake, to the nearest tenth of a kilometer?
5.7 km
6.3 km
11.4 km
16.0 km

Answers

Answer:

The first option (5.7km)

Step-by-step explanation:

Since we have a right angle triangle and we know two of its sides we can easily find out the thirds side (the value of d) by using the Pathagoras Theorem. In our case 7 and d are our legs and the hypotenuse is equal to 9, so...

(Based on the Pathagoras Theorem)

[tex]c^{2} = a^{2} + b^{2}[/tex]

[tex]9^{2} = 7^{2} + d^{2}[/tex]

[tex]d^{2} = 9^{2} - 7^{2} \\d^{2} = 81 - 49\\d^{2} = 32\\d = \sqrt{32}\\[/tex]

d ≈ 5.7km

There for aproximate distance across the lake is equal to 5.7km

Answer:

Step-by-step explanation:

Ypu deposit $200 in an account that earns 4% simple interest. How much interest did you earn in 3 years?

Answers

Answer:

$1200

Step-by-step explanation:

we know that,

I=PTR/100=200*4*3/100=100*4*3=400*3=$1200

Answer:

1,200

Step-by-step explanation:

Determine the solution to the system of equations

{8x-3y=-11
-4x+2y=6}

And write your solution as an ordered pair.

Help!!

Answers

Answer:

no sé pero no se y no se y más no se

673. Решите уравнения:
1) x: 5,8 = 365;
3) x: 8,1 = 0,15;
2) x : 8,4 = 2,3;
4) x: 0,22 = 4,9.

Answers

Answer:1 ) x: 5.8 = 365

Step-by-step explanation:

x = 365 × 5.8

x = 2117

2117: 5.8 = 365

2) x: 8.4 = 2.3

x = 2.3 × 8.4

x = 19.32

19.32: 8.4 = 2.3

3) x: 8.1 = 0.15

x = 0.15 X 8.1

x = 1.215

1.215: 8.1 = 0.15

4) x: 0.22 = 4.9

x = 4.9 x 0.22

x = 1.078

1.078: 0.22 = 4.9

a car travled 20 miles in 0.4 hours. what was the cars speed? Include units of measure.

Answers

Answer:5

Step-by-step explanation:∧

speed=distance/time

distance=20 miles

time=0.4

speed=20/0.4

Answer=5

Solve the following triangle

Answers

Answer:

Step-by-step explanation:

as , 77+x = 146(external angle) , so x = 146 - 77

so x = 69

Answer:

Step-by-step explanation:

hope you'll now how to do it by ur own.

72 paper clips to 63 paper clips

Answers

Answer:

72>63

Step-by-step explanation:

what is the rest of the question like in what form

Evaluate m3 + n3 for m = 3, n = 2.
O A. 8
O B. 27
O C. 35
O D. 15

Answers

it’s D(15)
(3)*3+(2)*3
9+6=15

First to answer gets brainliest

Answers

55>5x+39 this is your equation and since he wants to stay under 55 you didn’t use the one with the line.

cinco ejemplos de incremento

Answers

Answer:

Ejemplos de incremento matemático que pueden ocurrir son:

-Suma: se adiciona una cantidad adicional a otra previamente existente. Ejemplo: 5 + 2 = 7, donde 5 es la cantidad inicial, y 2 es la cantidad adicional, sumando 7 como cantidad final.

-Multiplicación: aquí se adiciona el mismo número inicial tantas veces como su multiplicador indique. Ejemplo: 5 x 3 = 15, donde el número inicial 5 es sumado 3 veces (5 + 5 + 5) para dar un total de 15.

-Potenciación: en este caso se multiplica el mismo número por sí, por la cantidad de veces que indique el número potenciador. Ejemplo: 7^2, donde 7 es multiplicado por 7 dos veces, es decir, 7 x 7, cuyo resultado es 49.

Así, cinco ejemplos de este tipo de operaciones pueden ser:

6^3 = 216

4x4 = 16

25+90 = 115

77 + 2x8 = 93

88 + 14 = 102

Please answer fast I need the Answer

Answers

Answer:

just do it urself

Step-by-step explanation:

HURRY
1.3(2x + 4) + 2(3x – 4)
2. Evaluate the expression for x=5

Answers

Answer:

According to my evaluations this equation is very petty and most likely has an answer. There are variables and numbers "3x". This part of the equation makes me feel special because 3 is a prime number. It is also mysterious because we dont know for sure what x is. This equation teaches the mathematician the true meaning of life. As it demonstrates the complexity, the information you know for sure and the information that you will learn in the future. The reader will also learn that not all problems can be solved and the ones that can be solved should be solved with varying difficulty. Finally the individual will realize that everyone has their own method to solve problems and go about life. In conclusion, this pretty equation teaches the mathematician about the importance of hard work and acceptance of everyone in their community.

Answer:

8.6x-2.8

Step-by-step explanation:

Also i feel like ik u from school or something.

There was this girl who had the exact last name and first name

4 movie tickets cost $35, how many dollars per ticket

Answers

8.75$ that’s the amount 35 divided by 4

Answer:

140

Step-by-step explanation:

35 x 4= 140

Take ur time i just need a anwser ;w;

Answers

Answer:20 people

Step-by-step explanation:

the standard form of the equation through the points (-2,-2) and (2,-1)

Answers

Answer:

y = 1/4x - 3/2

Step-by-step explanation:

for slope, use formula (y2-y1)/(x2-x1):

(-1-(-2))/(2-(-2))

=1/4

use formula y=mx+b for equation:

y=1/4x+b (substitute x and y for either (-2, -2) or (2, -1))

-1=1/4(2)+b

-1=1/2+b

-3/2 = b

equation:

y = 1/4x - 3/2

Find the value of x. Round to the nearest tenth.

Answers

Answer:

x = 11.8

Step-by-step explanation:

Side a = 11.78983

Side b = 3

Side c = 10

Angle ∠A = 120° = 2.0944 rad = 2/3π

Angle ∠B = 12.731° = 12°43'50" = 0.22219 rad

Angle ∠C = 47.269° = 47°16'10" = 0.82501 rad

The answer for x is 11.8

Jim needs to move his firewood from his truck to the woodpile in his house. He estimates that he will move 1/8 of the total wood in 45 minutes. Which unit rate can he use to help him plan how long it will take for him to move all the firewood?
Please explain how you got to answer

Answers

1/6 of the wood in one hour. Let me help you with future problems i use this app called socratic it helps alot trust

1. Given: Angle 2 is 65 degrees.

(a) What is the angle measurement of Angle 4. Explain the angle relationship used and show your work.
(b) What is the angle measurement of Angle 7. Explain the angle relationship used and show your work.
(c) What is the angle measurement of Angle 3. Explain the angle relationship used and show your work.

Answers

Answer:

Part A. Angle 4 is 115 Part B. angle 7 is 65 Part C angle 3 is 65

Step-by-step explanation: Part A. Is a corresponding angle of 1 and 4 Part B. alternate exterior angle of 2 Part C. corresponding angle of 7

Treyvion runs a total of 48 miles in 12 days, how many miles can he run in 20 days?

Answers

Answer:

80 miles in 4 days.

Step-by-step explanation:

48/12 = 4

4 miles per day

4 × 20 = 80

80 miles in 4 days

These figures are congruent. What is the measurement? pic below

Answers

Answer:

i dont know

Step-by-step explanation:

Tell whether the ordered pair is a solution to the system of linear equations. 1 point
(-4,-2);
y = 2.c + 6
y = -32 – 14
Yes
No
O Maybe

Answers

Answer:

Yes

(-4,-2) is a solution of a given system of equation

Step-by-step explanation:

Explanation:-

Given that the equation

y = 2 x + 6 ..(i)

Given point (-4,-2)

substitute x =-4 and y = -2 in equation (i)

-2 =2(-4) +6

-2 = -8+6

-2 =-2

∴ The point satisfies the given equation

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