In the equation for surface area the radius is squared ( r^2)
If the radius is doubled, the radius would be 2^2 more which equals 4
The surface area would be 4 times the old surface area.
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.
Answer:
24/35 hours or 0.69 hours
Step-by-step explanation:
we know that
The speed is equal to divide the distance by the time
Let
x-----> distance traveled by John
(24-x) ----> distance traveled by Ramona
The time is equal to divide the distance by the speed
so
x/20=(24-x)/15
15x=20(24-x)
15x=480-20x
15x+20x=480
35x=480
x=480/35 miles
the time is equal to
t=x/20
t=480/(20*35)=24/35=0.69 hours
14 my teacher just told me the answer
Answer:
57°
Step-by-step explanation:
LHS angle=RHS angle=57° (vert. opp angles)
