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The average age of an adult class is 40 years. 12 new students with an average age of 32 years join the class, thereby decreasing the average by 4 years. The original strength of the class was-
Answer & Solution
Correct Answer:
Option
C
Let the original strength of the class be x
Sum of ages of the whole class = 40x years
Sum of ages of 12 now students
= (12 × 32) years
= 384 years
∴ $$\frac{40x + 384}{x + 12}$$ = 36
⇒ 40x + 384 = 36x + 432
⇒ 4x = 48
⇒ x = 12
Hence, the original strength of the class = 12
Sum of ages of the whole class = 40x years
Sum of ages of 12 now students
= (12 × 32) years
= 384 years
∴ $$\frac{40x + 384}{x + 12}$$ = 36
⇒ 40x + 384 = 36x + 432
⇒ 4x = 48
⇒ x = 12
Hence, the original strength of the class = 12
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