Without speeding up it would take 5 1/3 seconds.. not sure if it speeds up in the question?
Answer:
First one:
Both the mean and median are greater for Plot A than for Plot B
Step-by-step explanation:
Set A:
Mean:
[1×10 + 2×7 + 2×6 + 2×5 + 2×4 + 1×3]/10
= 5.7
Median:
Median position: (10+1)/2 = 5.5th value
(5+6)/2
Median = 5.5
Set B:
Mean:
[1×7 + 3×6 + 3×5 + 2×4 + 1×3]/10
= 5.1
Median:
Median position: (10+1)/2 = 5.5th value
(5+5)/2
Median = 5
Mean: A is greater
Median: A is greater
143 is composite. To be prime it has to have only 2 divisors i.e it's self and one but since it has 4 divisors ( 143, 1, 11 and 13) it is composite.
Speed of the plane: 250 mph
Speed of the wind: 50 mph
Explanation:
Let p = the speed of the plane
and w = the speed of the wind
It takes the plane 3 hours to go 600 miles when against the headwind and 2 hours to go 600 miles with the headwind. So we set up a system of equations.
600
m
i
3
h
r
=
p
−
w
600
m
i
2
h
r
=
p
+
w
Solving for the left sides we get:
200mph = p - w
300mph = p + w
Now solve for one variable in either equation. I'll solve for x in the first equation:
200mph = p - w
Add w to both sides:
p = 200mph + w
Now we can substitute the x that we found in the first equation into the second equation so we can solve for w:
300mph = (200mph + w) + w
Combine like terms:
300mph = 200mph + 2w
Subtract 200mph on both sides:
100mph = 2w
Divide by 2:
50mph = w
So the speed of the wind is 50mph.
Now plug the value we just found back in to either equation to find the speed of the plane, I'll plug it into the first equation:
200mph = p - 50mph
Add 50mph on both sides:
250mph = p
So the speed of the plane in still air is 250mph.
