Answer:
............................
Step-by-step explanation:
(a) Average time to get to school
Average time (minutes) = Summation of the two means = mean time to walk to bus stop + mean time for the bust to get to school = 8+20 = 28 minutes
(b) Standard deviation of the whole trip to school
Standard deviation for the whole trip = Sqrt (Summation of variances)
Variance = Standard deviation ^2
Therefore,
Standard deviation for the whole trip = Sqrt (2^2+4^2) = Sqrt (20) = 4.47 minutes
(c) Probability that it will take more than 30 minutes to get to school
P(x>30) = 1-P(x=30)
Z(x=30) = (mean-30)/SD = (28-30)/4.47 ≈ -0.45
Now, P(x=30) = P(Z=-0.45) = 0.3264
Therefore,
P(X>30) = 1-P(X=30) = 1-0.3264 = 0.6736 = 67.36%
With actual average time to walk to the bus stop being 10 minutes;
(d) Average time to get to school
Actual average time to get to school = 10+20 = 30 minutes
(e) Standard deviation to get to school
Actual standard deviation = Previous standard deviation = 4.47 minutes. This is due to the fact that there are no changes with individual standard deviations.
(f) Probability that it will take more than 30 minutes to get to school
Z(x=30) = (mean - 30)/Sd = (30-30)/4.47 = 0/4.47 = 0
From Z table, P(x=30) = 0.5
And therefore, P(x>30) = 1- P(X=30) = 1- P(Z=0.0) = 1-0.5 = 0.5 = 50%
Times 4 because, 5 times 4 is 20, 20 times 4 is 80 and so on.
Answer:
Yes it is, because...
Step-by-step explanation:
This is an inequality, so you can treat it as an algebraic expression.
The first step is to multiple both sides by 2, to get rid of the 2 on the left side.
Your equation will now look like this:
y >= 2y - 22
The next step is to get all the y variables to one side, now that its a lot more simplified. Subtract 2y from both sides to get:
-y >= -22
Finally, cancel out the negative on both sides of the equation to get the y as a positive y, all by itself. This will get you:
y <= 22
REMINDER: when you divide by a negative number, such as in this case dividing by -1 on both sides, the inequality sign will flip!
y = 18 works because it is less than 22. (:
