If you divide 380 by 20, you get 19. To check this, multiply 20 x 19 to see 380. Hope this helps :D
Answer:
Expected value = 190
Variance = 4000
Step-by-step explanation:
Let X be the number of the trials until the third success of the bad pump.
This implies that X is a negative binomial distribution
having θ = 20% = 0.2.
Now, if for example it will take X trials to use up the three pumps, then the total time is 10 min/trials + extra 10 minutes for the 3 bad pumps
This means the total time is written as;
T = 10X + (10 + 10 + 20)
T = 10X + 40
Mean which is also expected value of X is;
μ_x = 3/0.2 = 15
Variance of X is; σ²_x = 40
Thus;
Mean of T will be;
μ_T = 10μ_x + 40
μ_T = 10(15) + 40
μ_T = 190
Also, variance of T will be;
σ²_T = 10²•σ²_x
σ²_T = 100 × 40
σ²_T = 4000
How should you write the proportion 9:36 = 10:40 using words?
A. 9 is to 36 as 40 is to 10
B. 9 is to 10 as 36 is to 40
C. 36 is to 9 as 10 is to 40
D. 9 is to 36 as 10 is to 40
Answer:
P ( x_bar > 335 ) = 0.9826
Step-by-step explanation:
Given:
- Mean amount u = 350
- standard deviation s.d = 45/year
- Sample size n = 40
Find:
- The probability of sample mean P( x_bar > 335 )
Solution:
- P ( x_bar > 335 ) = P ( Z > sqrt(n)*(x_bar - u)/s.d)
= P ( Z > sqrt(40)*(335-350)/45)
= P ( Z > -2.111) = P ( Z < 2.111)
= 0.5 + P( 0 < Z < 2.111)
= 0.5 + 0.4826
= 0.9826
I'm horrible at this so I'm just guessing.
X is the variable and x means multiplication symbol.
X + (X x 3 - 1) + (X x 3 - 1) - 4) <span>≥ 45 is the answer I got.
The answer to that inequality would be
X </span><span>≥ 7 I think.</span>
