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The average age of 25 students is 16 years Find the average age if a teacher aged 42 years is included
Answer is 17.
You can use the normal method which would be ((25*16)+42)/26 which would give the answer of 17.
The calculation will be a bit tedious... on the other hand think of the solution like this.
Currently 25 students are there avg is 16yrs. If the 26th person gets added with average age 16 then the average will be the same as 16. BUT since the age of teacher is 42. We do these calculation.. (42-16=26). The 26th person has 26 extra age... this 26th extra age will get added by 1 to each student increasing the average to 17. This method is much easier and quicker to solve if you have grasped the knowledge of average.
Let's say if the age of teacher was..55 We would proceed with (55-16=39). Now 39 has to be distributed to 26 persons. So the new average would be 17.5. (Since 39/26=1.5, so adding 1.5 to 16 gives 17.5).
19 is incorrect.<br>Average = (25*16+42)/26 = 17.<br><br>Shortcut :<br>Subtract 16 from 42 and divide by 26 = 1.
Add it to the old average = 16+1 = 17.
We are adding because we can see that the age of teacher is greater than all students average.
So adding the teacher will increase the average.
So 17 should be the new average age.
