(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%
Answer:
Step-by-step explanation:
A highway engineer wants to compute the change in elevation of a section of road. The horizontal distance of this section of road is 2km and downgrade is 8%
The slope formula is given by
m = 8% = 8/100
run = y = 2km
Verification:
%
Answer:
1:4 and 3:12
Step-by-step explanation:
They are equivalent! Hope this helps! :)
Answer:
I did my best, but it has been a while. I really hope that this helps
Step-by-step explanation:
so you can find the perimeter of a circle
-----The perimeter of a circle is π × d where d is the diameter so half of that is 1/2 π × d. But If you are going to walk around a semicircle, you need to go halfway around the circle and then across a diagonal to get back to where you started, so the perimeter is 1/2 π × d + d.
Gave away 7 ⇒ -7
Bought 6 ⇒ + 6
Left with 13
If he did not buy the 6 cars ...
13 - 6 = 7
If he did not give the 7 cars away ...
7 + 7 = 14
He has 14 cars at first.
13 - 6
