(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:
0.95, 2.15
Step-by-step explanation:
cookie-x
ice bar-y
7x+2y=10.95 (*3)
4x+3y=10.25 (*2)
21x+6y=32.85
8x+6y=20.5
21x-8x=32.85-20.5=12.35
13x=12.35
x=0.95
2y=10.95-7*0.95=4.3
y=2.15
Answer:
B.
Step-by-step explanation:
A goes up by 1
C goes up by 8
D goes up by 5
But B increments by 2x (2 times)
You can also multiply the decimals by a multiple of 10 to turn them I to whole numbers. Just make sure you multiply them both by the same multiple of 10 and divide them back before you write your answer!
Step-by-step explanation:
RP = 67.7 feet
