Numerical expressions use numbers and algebraic expressions use variables.
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Complete Question
The life of a semiconductor laser at a constant power is normally distributed with a mean of 7,000 hours and a standard deviation of 600 hours. If three lasers are used in a product and they are assumed to fail independently, the probability that all three are still operating after 7,000 hours is closest to? Assuming percentile = 95%
Answer:
0.125
Step-by-step explanation:
Assuming for 95%
z score for 95th percentile = 1.645
We find the Probability using z table.
P(z = 1.645) = P( x ≤ 7000)
= P(x<Z) = 0.95
After 7000 hours = P > 7000
= 1 - P(x < 7000)
= 1 - 0.95
= 0.05
If three lasers are used in a product and they are assumed to fail independently, the probability that all three are still operating after 7,000 hours is calculated as:
(P > 7000)³
(0.05)³ = 0.125
Answer:
52min
Step-by-step explanation:
5 people..............5 walls............52 min
1 people...............5 walls...........52 x 5=260 min
1 people................20 walls.........260 x 4 =1040 min
20 people................20 walls........1040:20=52 min
Answer:
The answer is 4.2 kilograms of dog food
Step-by-step explanation:
it says that ray feeds his dog 0.12 kilogram of food each day
he needs for 1 month
1 month = 31 days or 30 days
since 1 day food is 0.12 kilograms you'll have to multiply 0.12 with 1 month
i.e; 0.12*31 or 0.12*30
0.12*31=3.72 and 0.12*30=3.6
since we don't have an option we'll have to choose something bigger than this
therefore, the answer is 4.2