Question

13 25 4 8 17 21 A number is to be written on the blank card. The mode and median of all seven numbers are both the same. Find one possible number that can be written on the blank card.​

Answer 1

13 or 17

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Given numbers:

• 13, 25, 4, 8, 17, 21

Put them in the ascending order:

• 4, 8, 13, 17, 21, 25

Let the possible number to be added be x.

Since x is the median, it should be between 13 and 17:

• 4, 8, 13, x, 17, 21, 25

Also x is the mode. As we see all 6 number are unique, x should be repeat of 13 or 17 in order to be a mode. Therefore the possible number that can be written on the blank card is either 13 or 17.