Answer:
15
Step-by-step explanation:
Hope this helps
Answer:
The expected value of X is 2 with a standard deviation of 1.34.
Step-by-step explanation:
For each speaker, there are only two possible outcomes. Either it is defective, or it is not. The probability of a speaker being defective is independent of other speakers. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:

The standard deviation of the binomial distribution is:

Stereo speakers are manufactured with a probability of 0.1 of being defective
This means that 
Twenty speakers are randomly selected.
This means that 
Let the random variable X be defined as the number of defective speakers. Find the expected value and the standard deviation.


The expected value of X is 2 with a standard deviation of 1.34.
Answer:
3 , 4 , 5 can formed right triangle
Step-by-step explanation:
In any triangle if the sum of the squares of the smallest two sides equals the square of the third side, then the triangle is right triangle
∵ 16² + 32² = 1280
∵ 36² = 1296 ≠ 1280 ⇒ Not right Δ
∵ 3² + 4² = 25
∵ 5² = 25 ⇒ right Δ
∵ 8² + 12² = 208
∵ 16² = 256 ≠ 208 ⇒ Not right Δ
∵ 9² + 10² = 181
∵ 11² = 121 ≠ 181 ⇒ Not right Δ