Answer:
0.969
Step-by-step explanation:
Given that:
Mean lifetime (m) = 520 hours
Variance = 900
Hence, standard deviation (s) = √900 = 30
Probability that bulb will last for at most 576 hours
X ≤ 576
Obtain the standardized score :
Using the relation :
Zscore = (x - m) / s
Zscore = (576 - 520) / 30
Zscore = 56 / 30
Zscore = 1.867
P(Z ≤ 1.867) : using the z probability calculator ;
P(Z ≤ 1.867) = 0.96905
Hence, P(Z ≤ 1.867) = 0.969
3.12 = 312/100
(÷4)
= 78/25
= 3 3/25
Hope it helped!
Answer:
402.123859659
Step-by-step explanation:
first we use A=πr2
this gives us A = 16π
Then multiply by 8 to get 128π
128π = 402.123859659
I believe the answer is B) 50
