Answer:
B
Step-by-step explanation:
-t²+4t+5=0
t²-4t-5=0
t²-5t+t-5=0
t(t-5)+1(t-5)=0
(t-5)(t+1)=0
t=5,-1
when t=0,d=5
actual time it it is in air=5-1=4 seconds.
Answer:
Step-by-step explanation:
Given that X is N(50,3)
So whenever we want score for x, we can convert this to Z and use std normal distribution table.
The formula for conversion is

Using this we can find out the corresponding scores
a) 
Z value = 1 and hence

b) 

c) 
d) 
e) 10th percentile is 
f) This is 99th percentile
=
Answer is in the attachment below.
Answer: The fraction 301/900
Note: I'm assuming the 4's continue on forever
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Work Shown:
I'm going to assume that the 4s go on forever. I'll represent this with three dots after the last 4 like so
0.334444...
Now let x = 0.334444...
Multiply both sides by 100
x = 0.334444...
100x = 100*(0.334444...)
100x = 33.444444...
And repeat with 1000
x = 0.334444...
1000x = 1000*(0.334444...)
1000x = 334.444444...
Then subtract and solve for x. Notice how the decimal parts line up and cancel
1000x-100x = (334.444444...) - (33.444444...)
1000x-100x = (334+0.444444...) - (33+0.444444...)
1000x-100x = 334+0.444444... - 33 - 0.444444...
1000x-100x = (334-33)+(0.444444... - 0.444444...)
900x = 334 - 33
900x = 301
x = 301/900