It’s 3.8 inches I’m pretty sure
Answer:
3^x + 12x -4
Step-by-step explanation:
f(x) = 3^x + 10x
g(x) = 2x - 4,
(f + g)(x) = 3^x + 10x + 2x - 4
Combine like terms
= 3^x + 12x -4
4(x - 2) + 6 = 2(5x - 6) <em>use distributive property</em>
(4)(x) + (4)(-2) + 6 = (2)(5x) + (2)(-6)
4x - 8 + 6 = 10x - 12
4x - 2 = 10x - 12 <em>add 2 to both sides</em>
4x = 10x - 10 <em>subtract 10 from both sides</em>
-6x = -10 <em>divide both sides by (-6)</em>
x = 10/6
<h3>x = 5/3</h3>
(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%
