60=4x+24
-24. -24
36=4x
36÷4
x= 9
she needs babysit 9 more hours to have enough for the bool series
You need to make a series of equations from what you are given first. I am going to use the first letter of each of the names to represent the length of that persons wire.
1/2s=2/5d
3c=s
s+d+c=6 ft
Okay. Now you can combine the first two equations knowing what s equals:
1/2(3c)=2/5d
d=15c/4
Now you have d=15c/4 and s=3c, so you can replace d and s in the third equation.
3c+15c/4+c=6
Then solve for c and plug it into the equation 3c=s to find the length of sarah's wire.
Answer:
20 miles with an error margin of ± 8 miles
Step-by-step explanation:
The margin of error of a result is the range in which an error can vary. To find the margin of error between both distances we have to
28-12 = 16, that is, the variation of the result has a range of 16 miles. So we will look for the midpoint of both distances
(X2-X1)/2+X1=(28-12)/2+12=16/2+12=8+12=20
So from this midpoint the value can vary between 8 points below and 8 points above that would cover the difference of 16 miles that we observed at the beginning
In this way, the correct answer is 20 miles with an error margin of ± 8 miles
Done
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