Answer:
0.8413 = 84.13% probability of a bulb lasting for at most 605 hours.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean 
and standard deviation 
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
The standard deviation of the lifetime is 15 hours and the mean lifetime of a bulb is 590 hours.
This means that 
Find the probability of a bulb lasting for at most 605 hours.
This is the pvalue of Z when X = 605. So
has a pvalue of 0.8413
0.8413 = 84.13% probability of a bulb lasting for at most 605 hours.
Answer: The toy should be 2.4 inches tall
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Explanation:
First convert 6 ft to inches
6 ft = (6 ft)*(12 in/1 ft) = (6*12) inches = 72 inches
So, 6 ft = 72 inches
The toy is manufactured with a scale of 1:30 meaning that the toy is 1 unit tall compared to the soldier which is 30 units tall. The soldier is 30 times taller than the toy. We can therefore form the ratio
1/30 = x/72
where x is the height of the toy soldier in inches
Cross multiply and solve for x
1/30 = x/72
1*72 = 30*x
72 = 30*x
72/30 = 30*x/30
72/30 = x
x = 72/30
x = 12/5
x = 2.4
So the toy should be 2.4 inches tall.
Note how 30 times 2.4 gives us
30*2.4 = 72
which fits with the theme that the real soldier is 30 times taller than the toy counter part.
Answer:
He made a mistake in the second line.
Step-by-step explanation:
He factored out x out of 6-2x and 5+4x, which is not possible because there is not an x in both 6 and 5.
The answer is -1 because, -2x+-6 = -4 is the same as -2x=2 which equals -1
6, 12, 18, 24.
8, 16, 24.
24 is your answer. Hoped I helped!
