Question

7 920 3 9(a)

A number is removed from this list and the median and range do not change. Write down this number.
a) 7
b) 9
c) 3
d) 20

Answer 1

The number that can be removed from the list without changing the median and range is the number 9, as it is neither the smallest, largest nor the only middle value in the list.

Step-by-step explanation:

The initial list of numbers is 7, 9, 20, 3, 9. To preserve the median and range, we need to eliminate a number that is neither the smallest, the largest, nor the middle value in the ordered list. When we arrange the numbers in ascending order we get 3, 7, 9, 9, 20. The median is 9, and the range is 20 - 3 = 17. Removing one of the 9s does not affect the median, since the remaining 9 still sits in the middle of the list, and it does not affect the range, as the smallest and largest numbers remain the same. Therefore, the number that can be removed is 9.