Answer:
<h2>0.75(3/4) part of the room</h2>
Step-by-step explanation:
Step one:
given data
we can express the given data mathematically as
John can paint 0.5room in 2/3 hours
let the part of the room he can paint in an hour be x
so
if he takes 2/3 hours to paint 0.5 room
then he will take 1 hour to paint x
cross multiply we have
x= 0.5/2/3
x=0.5*3/2
x= 1.5/2
x=0.75 part of the room
75/100= 15/20=3/4 part
Answer:
I think no A. x = -1/2 ,x = -4
The airplane reaches its maximum height of 81 feet in 12 seconds.
<h3>Behavior of curves</h3>
If y =
, it means that the second derivate is 2 which is positive, then there is a minimum turning point.
If y = -
, it means that the second derivative will be -2 which is negative, then there is a maximum turning point.
Analysis:
h(t) = -
+ 81
By expanding,
h(t) = -(
- 24t + 144) +81
h(t) = -
+ 24t - 144 + 81
h(t) = -
+ 24t - 63
at turning point d/dt(h(t)) = 0
d/dt (h(t)) = -2t +24
-2t +24 = 0
if we differentiate again, second derivative is -2 which is negative, so it is a maximum point.
2t = 24
t = 12 seconds
h(t) at t = 12
h(t) =
+ 24(12) - 63 = 81 feet
In conclusion, the maximum height of the airplane after 12 seconds is 81 feet.
Learn more about minimum and maximum points: brainly.com/question/14993153
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