Answer:
121.5
Step-by-step explanation:
Find the mean of the last 4 numbers.
4-7x=5
+7x +7x
4= 12x
/12 /12
x= 4/12
x= 1/3
Answer:
The rate at which the distance from the plane to the station is increasing is 331 miles per hour.
Step-by-step explanation:
We can find the rate at which the distance from the plane to the station is increasing by imaging the formation of a right triangle with the following dimensions:
a: is one side of the triangle = altitude of the plane = 3 miles
b: is the other side of the triangle = the distance traveled by the plane when it is 4 miles away from the station and an altitude of 3 miles
h: is the hypotenuse of the triangle = distance between the plane and the station = 4 miles
First, we need to find b:
(1)

Now, to find the rate we need to find the derivative of equation (1) with respect to time:
Since "da/dt" is constant (the altitude of the plane does not change with time), we have:
And knowing that the plane is moving at a speed of 500 mi/h (db/dt):
Therefore, the rate at which the distance from the plane to the station is increasing is 331 miles per hour.
I hope it helps you!
Answer:
1/10 per sec
Step-by-step explanation:
When he's walked x feet in the eastward direction, the angle Θ that the search light makes has tangent
tanΘ = x/18
Taking the derivative with respect to time
sec²Θ dΘ/dt = 1/18 dx/dt.
He's walking at a rate of 18 ft/sec, so dx/dt = 18.
After 3seconds,
Speed = distance/time
18ft/sec =distance/3secs
x = 18 ft/sec (3 sec)
= 54ft. At this moment
tanΘ = 54/18
= 3
sec²Θ = 1 + tan²Θ
1 + 3² = 1+9
= 10
So at this moment
10 dΘ/dt = (1/18ft) 18 ft/sec = 1
10dΘ/dt = 1
dΘ/dt = 1/10 per sec