(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:
A. 2a+6
Step-by-step explanation:
I did the test and this is what I got.
Fraction form: x=7/12
Steps:
64^4x-3
2^6(4x-3)=2^-4
6(4x-3)=-4
4x-3=-2/3
4x=7/3
X=7/12
Answer:
153.8 I guess... this is your answer
Answer:
10.44 m
Step-by-step explanation:
Solve this as a triange. The base is 3m and the perpendicular is 10m. The angle between the base and wall is 90° so it will be a right angled triangle.
Solve this by Pythagoras theorm:
let length of ladder is c
base is b
And perpendicular is a
Acc to Pythagoras theorem:
C² = a² + b²
C² = 10² + 3²
C² = 100 + 9
C² = 109
√C² = √109
C = 10.44m
