The average age of a class of 20 students is 18 years. A student whose age is 18 years joins the class. Find the new average age of the class (in years)?a.20b.22c.18d.19
Question
The average age of a class of 20 students is 18 years. A student whose age is 18 years joins the class. Find the new average age of the class (in years)?a.20b.22c.18d.19
Solution
The total age of the 20 students is 20*18 = 360 years.
When a new student whose age is 18 years joins the class, the total age becomes 360+18 = 378 years.
The total number of students is now 21.
So, the new average age of the class is 378/21 = 18 years.
Therefore, the answer is c.18.
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