If average of x and 1/x is 5/2, x is MCQ with Answer and Explanation

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If average of x and 1/x is 5/2, x is

A. 5

B. 4

C. 2 or 0.5

D. 1

Answer: Option C

Solution (By JKExamLibrary)

(x +1/x)/2 =2.5. x +1/x=5. x^2 -5x +1=0. x= [5±sqrt21]/2 but options for simple 2: (2+0.5)/2=1.25 no. Use valid.

This question belongs to: Maths Average

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If average of 12 numbers is 35 and average of first 8 is 32, average of last 4?

A. 40

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D. 42

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Correct Answer: Option C

Explanation:
Sum12=420. Sum8=256. Last4=164. Average=41.

This question belongs to: Maths Average

Question #2 Report Error

What is the average of the first 5 composite numbers?

A. 7.4

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C. 8.0

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Average of 12 numbers 570. If average of 8 is 565, average of remaining 4?

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