KVPY2019MathematicsStatistics
Let x 1 , x 2 , … , x 11 be 11 distinct positive integers. If we replace the largest of these integers by the median of the other 10 integers, then
Options
- Athe median remains the same
- Bthe mean increases
- Cthe median decreases
- Dthe mean remains the same
Correct answer
D. the mean remains the same
Step-by-step solution
Let the given 11 distinct positive integers are in increasing order x 1 , x 2 , x 3 , x 4 , x 5 , x 6 , x 7 , x 8 , x 9 , x 10 , x 11 , so x 11 is largest of these integers and the median is x 6 . Now, median of first 10 numbers is x 6 + x 6 2 = m (  Let  ) Now, we have to replace largest number x 11 by m and then increasing order will be x 1 , x 2 , x 3 , x 4 , x 5 , m , x 6 , x 7 , x 8 , x 9 , x 10 ∵    m < x 6 as x 5 < x 5 + x 6 2 < x 6 So, median decreases.