A common ratio for that sequence is r = 5/1
Hello! Your answer is B, 10 minutes.
Say the x = minutes taken to do the job. You can set up an equation like this to solve this.
![\frac{1}{15} x + \frac{1}{30} x = 1](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B15%7D%20x%20%2B%20%5Cfrac%7B1%7D%7B30%7D%20x%20%3D%201)
This is representative of the situation. The fractions each represent <u>how much each person does in a minute</u>, and when they're multiplied by x, that's <u>how much of the project they get done</u> based off of the minutes they work together on the job. Add the two together, and you get <u>how much of the project is finished in x amount of time</u>. Set it equal to 1, as you are looking for 100% completion.
Once you have this equation, find a common denominator, add, and solve.
![\frac{1}{15} x + \frac{1}{30} x = 1](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B15%7D%20x%20%2B%20%5Cfrac%7B1%7D%7B30%7D%20x%20%3D%201)
![\frac{2}{30} x + \frac{1}{30} x = 1](https://tex.z-dn.net/?f=%5Cfrac%7B2%7D%7B30%7D%20x%20%2B%20%5Cfrac%7B1%7D%7B30%7D%20x%20%3D%201)
![\frac{3}{30}x = 1](https://tex.z-dn.net/?f=%5Cfrac%7B3%7D%7B30%7Dx%20%3D%201)
![\frac{1}{10}x = 1](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B10%7Dx%20%3D%201)
![x = 10](https://tex.z-dn.net/?f=x%20%3D%2010)
Therefore, it will take them 10 minutes to do the job together.
Hope this helps!
She can travel <span>665.4375 miles in 68.25 min.</span>
Answer:
B. 0.4
Step-by-step explanation:
Use the definition of the probability
![Pr=\dfrac{\text{Number of all favorable outcomes}}{\text{Number of all possible outcomes}}](https://tex.z-dn.net/?f=Pr%3D%5Cdfrac%7B%5Ctext%7BNumber%20of%20all%20favorable%20outcomes%7D%7D%7B%5Ctext%7BNumber%20of%20all%20possible%20outcomes%7D%7D)
You have to find the probability that a randomly selected reference book is hard cover. Hence, from the table
- Number of all possible outcomes = Number of Reference books = 25
- Number of all favorable outcomes = Number of Hardcover Reference books = 10
So, the probability is
![Pr=\dfrac{10}{25}=\dfrac{40}{100}=0.4](https://tex.z-dn.net/?f=Pr%3D%5Cdfrac%7B10%7D%7B25%7D%3D%5Cdfrac%7B40%7D%7B100%7D%3D0.4)