Average of x, y and 15 is 9, so sum = x+y+15=9*3......x+y=12

A. average of x +y, so \(\frac{x+y}{2}=\frac{12}{2}=6\)
B. 6

so both are equal

C

GIVEN: The average (arithmetic mean) of x, y, and 15 is 9

We can write: \(\frac{x+y+15}{3}=9\)

Multiply both sides by 3 to get: \(x+y+15=27\)

Subtract 15 from both sides to get: \(x+y=12\)

We get:
Quantity A: average of x and y \(= \frac{x+y}{2}= \frac{12}{2}=6\)
Quantity B: 6

Answer: C

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The average (arithmetic mean) of x , y and 15 is 9.

Quantity A	Quantity B
Average of x and y	6

A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.

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Theory

‣‣‣ Mean or Average = (Sum Of All The Numbers) / (Total Number Of Numbers)

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Average of x, y and 15 is 9

=> \(\frac{x + y + 15}{3}\) = 9
=> x + y + 15 = 9*3 = 27
=> x + y = 27 - 15 = 12

Quantity A: Average of x and y

Average of x and y = \(\frac{x + y }{2}\) = \(\frac{12}{2}\) = 6

Clearly, Quantity A = Quantity B = 6

So, Answer will be C.
Hope it helps!

Watch the following video to Learn the Basics of Statistics

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