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The average of a non-zero number and its square is 5 times the number. The number is-
Answer & Solution
Correct Answer:
Option
A
Let the number be x
Then,
$$\eqalign{ & \Rightarrow \frac{{x + {x^2}}}{2} = 5x \cr & \Rightarrow {x^2} - 9x = 0 \cr & \Rightarrow x\left( {x - 9} \right) = 0 \cr & \Rightarrow x = 0{\text{ or }}x = 9 \cr} $$
So, the number is 9
Then,
$$\eqalign{ & \Rightarrow \frac{{x + {x^2}}}{2} = 5x \cr & \Rightarrow {x^2} - 9x = 0 \cr & \Rightarrow x\left( {x - 9} \right) = 0 \cr & \Rightarrow x = 0{\text{ or }}x = 9 \cr} $$
So, the number is 9
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