In a class, the average age of 40 students is 12 years when teacher’s age is included to it, the average increases by 1. The age of teacher is :
Let Teacher's age be x
Average age $$=\frac{40\times12+1\times x}{41}=13$$
$$\Rightarrow x = 533-480$$
$$\Rightarrow x =53$$
Option A is correct.
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