Answer:
0.02275
Step-by-step explanation:
We have been given that the time needed to complete a final examination in a particular college course is normally distributed with a mean of 80 minutes and a standard deviation of 10 minutes. We are asked to find the probability of completing the exam in one hour or less.
We know that 1 hour equals 60 minutes. First of all, we will find the z-score corresponding to 60 minutes.

z = z-score,
x = Sample score,
= Mean,
= Standard deviation.



Now, we will use normal distribution table to find area under z-score of
as:


Therefore, the probability of completing the exam in one hour or less is 0.02275.
3/5 = 60%
20 ÷ 5 = 4
3 x 4 = 12
Answer is A) 12/20
x²/2 =271 represents the situation where taking length twice as breadth and area as 271 ft² .
Area of a figure is the amount of space acquired by the figure
Area of a rectangle=Length x breadth
length=x
breadth=x/2
Area of rectangular lawn=lxb
=x.x/2
But as per question,
Area=271 ft²
⇒x²/2=271 1
⇒x=23.28 ft²
Therefore, x²/2 =271 represents the situation where taking length twice as breadth and area as 271 ft² .Value of x i.e. length is 23.28 ft²
Learn more about area,
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