If the amount of time taken to go said distance is x and the amount of time taken to go back said distance is y, then the amount of miles total is 7x+3y due to that for every hour, she adds 7 miles when going there and 3 miles for walking back. In addition, since the total amount of time is 4 hours, x+y=4 as the total time spent as well as 7x=3y due to that they're the same distance.
x+y=4
7x=3y
Dividing the second equation by 7, we get x=3y/7. Plugging that into the first equation, we get 3y/7+y=4=10y/7 (since y=7y/7). Multiplying both sides by 7 and then dividing both by 10, we get 28/10=2.8=y in hours. Since 0.1 hours is 60/10=6 minutes, and 0.8/0.1=8, 6*8=48 minutes=0.8 hours, meaning that she should plan to spend 2 hours and 48 minutes walking back
Answer:
About 5 hr 10 min
Step-by-step explanation:
rate 1 = 1 pool / 9 hrs rate 2 = 1 pool / 12 hours
now find the time with both rates combined
1 pool / ( 1/9 + 1/12) = 1/ (7/36) = 36/7 hr = 5 1/7 hr = 5 hr 8.6 min
Using the hypergeometric distribution, it is found that there is a 0.0065 = 0.65% probability that both David and Valerie get picked for the Tahitian dance lesson.
The people are chosen without replacement from the sample, hence the <em>hypergeometric distribution </em>is used to solve this question.
<h3>What is the
hypergeometric distribution formula?</h3>
The formula is:
The parameters are:
- x is the number of successes.
- N is the size of the population.
- n is the size of the sample.
- k is the total number of desired outcomes.
In this problem:
- There is a total of 18 people, hence .
- 2 people will be chosen, hence .
- David and Valerie corresponds to 2 people, hence .
The probability that both get picked is P(X = 2), hence:
0.0065 = 0.65% probability that both David and Valerie get picked for the Tahitian dance lesson.
You can learn more about the hypergeometric distribution at brainly.com/question/25783392
Day 1: 4
Day 2: 2 (2+4=6)
Day 3: 2 (2+4+2=8)
Day 4: 2 (2+4+2+2=10)
Day 5: 2 (2+4+2+2+2=12)
Day 6: 2 (2+4+2+2+2+2=14)
Day 7: 2 (2+4+2+2+2+2+2=16)
She sold for a week/7 days.