Complete question :
The lifetimes of a certain type of calculator battery are normally distributed. The mean lifetime is 400 days, with a standard deviation of 50 days. For a sample of 6000 new batteries, determine how many batteries will last: 360 and 460 days
Answer:
0.67307
Step-by-step explanation:
Given that :
Mean, m = 400
Standard deviation, s = 50
Sample size, n = 6000
Obtain the standardized score :
Zscore =(x - m) / s
For X = 360
P(x < 360)
Zscore =(360 - 400) / 50
Zscore = - 40 / 50
Zscore = - 0.8
P(Z < - 0.8) = 0.21186
For X = 460
P(x < 460)
Zscore =(460 - 400) / 50
Zscore = 60 / 50
Zscore = 1.2
P(Z < 1.2) = 0.88493
P(Z < 1.2) - P(Z < - 0.8)
0.88493 - 0.21186
= 0.67307
Answer:
8
Step-by-step explanation:
Step 1: There are 9000 sweets right?
and she puts 45 per packet, so do 9000 ÷ 45 and you should get 200
Step 2: She puts in 25 per box so then Do 200 ÷ 25 and you should get your answer of 8 boxes
Answer:
Step-by-step explanation:
This is most easily solved with calculus, believe it or not. It is way more direct and to the point, with a whole lot less math!
The position function is given. The velocity function is the first derivative of the position, so if we find the velocity function and set it equal to 0, we can solve for the amount of time it takes for the rocket to reach its max height. Remember from physics that at the top of a parabolic path, the velocity is 0.
If:
, then the velocity function, the first derivative is:
v(t) = -32t + 112 and solve for t:
-112 = -32t so
t = 3.5 seconds. Now we know how long it takes to get to the max height, we just need to find out what the max height is.
Go back to the position function and sub in 3.5 for t to tell us that position of the rocket at 3.5 seconds, which translates to the max height:
and
s(3.5) = 206 feet. I imagine that your answer, if you had to choose one from the list, would be 200 feet, rounded a lot.
Answer:
13
Step-by-step explanation:
formula: a^2 + b^2 = c^2
5^2 + 12^2 = c^2
25 + 144 = c^2
169 = c^2
13 x 13 = 169
13