Question

Find arithmetic mean of 9 and 21.

Answer 1

Answer:

15 is the arithmetic mean of 9 and 21

Step-by-step explanation:

I hope it can help you

Answer 2

SOLUTION

TO DETERMINE

The arithmetic mean of 9 and 21

EVALUATION

Let x be the arithmetic mean of 9 and 21

Then 9 , x , 21 are in Arithmetic Progression

So by the given condition

x - 9 = 21 - x

⇒ x + x = 21 + 9

⇒ 2x = 30

⇒ x = 15

FINAL ANSWER

The arithmetic mean of 9 and 21 is 15

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