This in what I got:
(-7i)(10i)
-70i
Hello!
First of all, we can subtract the stretching time. This gives us 20. If we divide by the four laps we get 5 minutes per lap.
Now, one lap is 400 meters (most tracks are), which is equal to 15,748.03 inches. This means it takes her five minutes to walk 15,748.03 inches. This is also equal to 300 seconds, so it takes her 300 minutes per 15,748.03 inches.
But if we round our big inches number to the nearest ten thousandth, we get 16,000, so in a simpler form her pace is 300/16,000. But we need to find in per second. Therefore we will divide by 300 to find how many inches she walks per second. This means she walks about 53.33 inches per second.
I hope this helps!
Answer:
Option 2) Null hypothesis: p = 0.078
, Alternate hypothesis: p > 0.078
Step-by-step explanation:
We are given the following in the question:
According to the National Center of Health Statistics, about 7.8% of all babies born in the U.S. are categorized as low birth weight.
Sample size, n = 1200
p = 7.8% = 0.078
We have to carry a hypothesis test whether national percentage is higher than 7.8% or not.
Thus, we can design the null and the alternate hypothesis

Thus, the correct answer is:
Option 2) Null hypothesis: p = 0.078
, Alternate hypothesis: p > 0.078
Answer:

Step-by-step explanation:
Assuming this problem :"Only 30% of the students in a certain liberal arts college are males.
If two students from this college are selected at random, what is the probability that they are both males?"
Previous concepts
An independent event is an "event that has no connection to another event's chances of happening ". For this case we can assume that if one person is male and if we select another one the probability that this one would be male or female is totally indepedent from the first selection.
When we have two independent events let's say A and B and we want to find the probability that both events occurs at the same time we can use the following formula:

Solution to the problem
We can define some notation:
first person selected is a male
second person selected is male
On this case we want the probability that both would be males. And we can express this like this on math terms:

For this case we can assume that the two events are independent. And in order to find the probability for two events independents events we just need to multiply the probabilities of each one like this:
