You need to work backwards
if it is no more than 9 units away from 8
thus x must be 8-9<x<8+9 solving -1<x<17
so the answer is 4.
9514 1404 393
Answer:
a) average rate = (total distance)/(total time)
b) Rave = 2·R1·R2/(R1 +R2)
c) cheetah's average rate ≈ 50.91 mph
Step-by-step explanation:
a) Let AB represent the distance from A to B. Let t1 and t2 represent the travel times (in hours) on leg1 and leg2 of the trip, respectively. Then the distances traveled are...
First leg distance: AB = 70·t1 ⇒ t1 = AB/70
Second leg distance: AB = 40·t2 ⇒ t2 = AB/40
The average rate is the ratio of total distance to total time:
average rate = (AB +AB)/(t1 +t2)
average rate = 2AB/(AB/70 +AB/40) = 2/(1/70 +1/40) = 2(40)(70)/(70+40)
average rate = 560/11 = 50 10/11 . . . mph
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No equations are given, so we cannot compare what we wrote with the given equations. In each step of the solution, we have used the rules of algebra and equality.
b) For two rates over the same distance (as above), the average is their harmonic mean:
average rate = 2r1·r2/(r1+r2)
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c) The cheetah's average rate was 50 10/11 mph ≈ 50.91 mph.
Answer:
The standard deviation of number of hours worked per week for these workers is 3.91.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean 
and standard deviation 
, the zscore of a measure X is given by
After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.
In this problem we have that:
The average number of hours worked per week is 43.4, so 
.
Suppose 12% of these workers work more than 48 hours. Based on this percentage, what is the standard deviation of number of hours worked per week for these workers.
This means that the Z score of 
has a pvalue of 0.88. This is Z between 1.17 and 1.18. So we use 
.
The standard deviation of number of hours worked per week for these workers is 3.91.
Answer:
choose "infinitely more solutions"
Step-by-step explanation:
Let's solve this system by substitution method
y+1=2x
- 1 = - 1
y = 2x -1 <-- sbstitute this in the next equation
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5y+5 = 10x
5(2x -1) + 5 = 10x
10x -5 + 5 = 10x
10x + 0= 10x
- 10x = -10x
0 = 0 <-- infinitely more solutions
Answer:
7x - 5y = -5 this is the standard form
