What is Mary biking speed in miles per hour

If - 4x + 6y = 9 and -2x – 7y = -8 are true equations, what would be the value of -2x + 13y?

UkoKoshka [18]

Answer:

17

Step-by-step explanation:

The expression of interest is the difference of the two given expressions.

(-4x +6y) -(-2x -7y) = (9) -(-8)

-2x +13y = 17

The value is 17.

_____

Additional comment

You could go to the trouble to solve the two equations for x and y, then compute the value of the expression you want. As we saw above, that is not necessary.

The first step in problem solving is always "look at the given information and how it relates to what you are asked." A little time spent doing that can save a lot of effort in the actual problem solving process.

6 0

3 years ago

One measure of general health is your body mass index (BMI). Adults with a BMI between 18.5 and 24.9 are generally considered to

soldi70 [24.7K]

Answer: 0.1797

Step-by-step explanation:

Given : $\mu=24.5\ \ ; \sigma=1.2$

Let x be the random variable that represents BMI for adults in this country.

We assume that BMI for adults in this country is normally distributed.

Then, z-score for x=25.6 , $\because z=\dfrac{x-\mu}{\sigma}$

$\Rightarrow\ z=\dfrac{25.6-24.5}{1.2}\approx0.9167$

Using z-value table , we have

The probability that the person's BMI is more than 25.6 :

$P(x>25.6)=P(z>0.9167)=1-P(z\leq0.9167)\\\\=1- 0.8203413=0.1796587\approx0.1797$

Hence, the probability that the person's BMI is more than 25.6 = 0.1797

Hence, the probability that the person's BMI is more than 25.6 = 0.1796

Hence, the probability of the stick's weight being 2.23 oz or greater = 0.0174

5 0

4 years ago

Pedro wants to walk from the historic village to the science center the he will walk from the science center to the museum.if he

Zepler [3.9K]

I'm assuming each grid square= 1 square mile.

To do this, you first need to find the total distance.
The first component of his walk takes him from an x-coordinate of 2 to a coordinate of -4 1/2. Since the y-value remains the same, you're not worried about that for this part of the problem. The difference between 2 and -4 1/2 is 6 1/2, so that is your horizontal distance.

Now he walks from the (-4 1/2, -1 3/4) to (-4 1/2, 5 1/4). This time, the x-value is constant, so you only need to worry about the y. As they are on opposite sides of the x-axis, you can add the y-values to get a result of 7, which is your vertical distance.

I just realized I did those distances in reverse order, but it should be ok because the total distance is the same.
To find the total distance, add vertical to horizontal.
6 1/2 + 7 = 13 1/2. This is your total distance.

Now that you have both his speed (given), and total distance, you can find the time it will take him. If he is moving at 4 1/2 mph and the distance is 13 1/2 miles, you can use s=d/t to find the time. 3 1/2 miles divided by the time = 4 1/2 mph. To solve for t, multiply both sides by t and divide that by s, so t= d/s. we know d= 13 1/2 and s= 4 1/2, so t= 13.5 divided by 4.5 = 3. As his speed is in mph, the unit is in hours. Therefore, the answer should be 3 hours.

5 0

3 years ago

Read 2 more answers

2(y - 6) = 3(y - 4) - y

max2010maxim [7]

Answer:

it has unlimited answers.

Step-by-step explanation:

4 0

4 years ago

Read 2 more answers

We call a number a descending number if each digit is strictly smaller than the digit that comes before it. For example, $863$ i

Mnenie [13.5K]

There are 120 of 3-digit descending numbers in total.

There is just one three-digit number that is a falling number if 2 is in the hundreds position, and that number is 210.

There are three such descending numbers if the number three is in the hundreds location.

310

320

321

Six descending numbers are available if 4 is in the hundreds place.

410

420

421

430

431

432

We have 10 descending numbers if the number five is in the hundreds location.

510

520

521

530

531

532

540

541

542

543

The current totals are: 1, 3, 6, and 10.

A +2 jump occurs from 1 to 3.

There is a +3 jump from 3 to 6.

From 6 to 10, there is a +4 jump.

Since there are 15 descending numbers and 6 is the hundreds digit, they are as follows: 610 620 621 630 631 632 640 641 642 643 650 651 652 653 654

Also included are the descending numbers 15+6 = 21 with the hundreds digit 7; 21+7 = 28 with the hundreds digit 8; and 28+8 = 36 with the hundreds digit 9.

They are 1,3,6,10,15,21,28, and 36.

1+3+6+10+15+21+28+36.

Equals 120 when added together.

Thus, there are 120 of 3-digit descending numbers in total.

Learn more about descending numbers at

brainly.com/question/13193576

#SPJ4

7 0

2 years ago