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
Jlenok [28]
3 years ago
15

A boat travels 45 miles upstream (against the current) in 5 hours. The boat travels the same distance downstream in 3 hours. Wha

t is the rate of the boat in still water? What is the rate of the current?
Mathematics
1 answer:
Leona [35]3 years ago
3 0
R=rate of boat in still water
c=rate of current
d=rt
since you're given that the time it takes to travel the same distance downstream and upstream, your equation will be d_1=d_2, or rt=rt
the rate upstream is r-c and the rate downstream is r+c (because the boat's and river's rates add up)
since you know t_1 and t_1 are 5 and 3, you can now set up 2 equations
<u>5*(r-c)=45</u> because (time upstream)*(rate upstream)=distance=45 miles
r-c=45/5=9
<u>3*(r+c)=45</u>
r+c=45/3=15
r-c=9 and r+c=15, so r=12 mi/h and c=3 mi/h
If you have any questions please ask
You might be interested in
A family buys airline tickets online. The family buys travel insurance that costs ​$ per ticket. The total cost is ​$. Let x rep
Nookie1986 [14]

Answer:

One ticket equals $169

Step-by-step explanation:

The family buys 4 airline tickets online.

The travel insurance costs $19 per ticket.

The total cost is $752.

A.

An equation that models this problem could be

Basically, we know that the insurance costs $19 which represents an additional costs after the price per ticket, that's why we need to add them. Then, we know that the familiy bought 4 tickes, that's why we multiply by 4, and finally, the total cost must be equal to 752, according to the problem.

B.

To find the price of one ticket, we just need to solve the equation for

Therefore, one ticket costs $169.

5 0
3 years ago
A piggy bank contains pennies, nickels, and dimes. The number of dimes is 15 more than the number of nickels, and there are 140
amm1812

Answer:

Option D is correct.

There are 34 nickels in the piggy bank.

Step-by-step explanation:

A piggy bank contains pennies, nickels and dimes.

Let the number of pennies be p

Let the number of nickels be n

Let the number of dimes be d

Also, note that 1 penny = $0.01

1 nickel = $0.05

1 dime = $0.10

- The number of dimes is 15 more than the number of nickels.

d = 15 + n

- There are 140 coins altogether totaling $7.17.

p + n + d = 140

0.01p + 0.05n + 0.1d = 7.17

Bringing the 3 equations together

d = 15 + n (eqn 1)

p + n + d = 140 (eqn 2)

0.01p + 0.05n + 0.1d = 7.17 (eqn 3)

Substitute (eqn 1) into (eqn 2)

p + n + d = 140

p + n + (15 + n) = 140

p + 2n + 15 = 140

p = 140 - 15 - 2n = 125 - 2n

p = 125 - 2n (eqn 4)

Substitute (eqn 1) and (eqn 4) into (eqn 3)

0.01p + 0.05n + 0.1d = 7.17

0.01(125 - 2n) + 0.05n + 0.1(15 + n) = 71.7

1.25 - 0.02n + 0.05n + 1.5 + 0.1n = 7.17

0.1n + 0.05n - 0.02n + 1.5 + 1.25 = 7.17

0.13n + 2.75 = 7.17

0.13n = 7.17 - 2.75 = 4.42

0.13n = 4.42

n = (4.42/0.13) = 34

d = 15 + n = 15 + 34 = 49

p = 125 -2n = 125 - (2×34) = 125 - 68 = 57

Hence, there are 57 pennies, 34 nickels and 49 dimes in the piggy bank.

Hope this Helps!!!

7 0
3 years ago
1 red bean for every 3 blue beans. Decimal equivalent of percent of red beans?
11111nata11111 [884]
The decimal equivalent is 0.25.
3 0
3 years ago
If t follows a t7 distribution, find t0 such that (a) p(|t | &lt; t0) = .9 and (b) p(t &gt; t0) = .05.
Thepotemich [5.8K]

Answer:

a) P(-t_o < t_7

Using the symmetrical property we can write this like this:

1-2P(t_7

We can solve for the probability like this:

2P(t_7

P(t_7

And we can find the value using the following excel code: "=T.INV(0.05,7)"

So on this case the answer would be t_o =\pm 1.895

b) For this case we can use the complement rule and we got:

1-P(t_7

We can solve for the probability and we got:

P(t_7

And we can use the following excel code to find the value"=T.INV(0.95;7)"

And the answer would be t_o = 1.895

Step-by-step explanation:

Previous concepts

The t distribution (Student’s t-distribution) is a "probability distribution that is used to estimate population parameters when the sample size is small (n<30) or when the population variance is unknown".

The shape of the t distribution is determined by its degrees of freedom and when the degrees of freedom increase the t distirbution becomes a normal distribution approximately.  

The degrees of freedom represent "the number of independent observations in a set of data. For example if we estimate a mean score from a single sample, the number of independent observations would be equal to the sample size minus one."

Solution to the problem

For this case we know that t \sim t(df=7)

And we want to find:

Part a

P(|t|

We can rewrite the expression using properties for the absolute value like this:

P(-t_o < t_7

Using the symmetrical property we can write this like this:

1-2P(t_7

We can solve for the probability like this:

2P(t_7

P(t_7

And we can find the value using the following excel code: "=T.INV(0.05,7)"

So on this case the answer would be t_o =\pm 1.895

Part b

P(t>t_o) =0.05

For this case we can use the complement rule and we got:

1-P(t_7

We can solve for the probability and we got:

P(t_7

And we can use the following excel code to find the value"=T.INV(0.95;7)"

And the answer would be t_o = 1.895

5 0
3 years ago
What is the factored form of 3x^2+21x-24
Oxana [17]

Answer:

3(x-1)(x+8)

Step-by-step explanation:

3x2+21x−24

3x2+21x−24

=3(x−1)(x+8)

8 0
3 years ago
Read 2 more answers
Other questions:
  • X to the power of 2 equal 100 how to solve
    6·2 answers
  • Need help on 2,3,4 thx!
    7·1 answer
  • Tatiana wrote the steps that are commonly used to solve a system of equations with two variables. Which steps are correct? Check
    13·2 answers
  • -1/2(2n+4)+6=-9+4(2n+1)
    14·1 answer
  • See the picture below!!!
    12·1 answer
  • Can someone please help
    11·1 answer
  • A population consisting of an unlimited number of unit is termed as
    13·2 answers
  • PLEASE HELP ME THIS IS SO IMPORTANT
    13·2 answers
  • In Heavenly Hash ice cream, the ratio of the amount of cashews to the amount of marshmallows to the amount of chocolate ice crea
    5·1 answer
  • Need the answer to the question
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!