Directions: Create a set of five positive integers from 1 to 20 that have the same mean, median, and range.

### Hint

### Hint

How can we create a set of five whole numbers where only two things (mean, median, and range) are the same?

### Answer

### Answer

There are many answers including

{2, 3, 4, 5, 6} mean, median, range = 4

{3, 4, 6, 8, 9 } mean, median, range = 6

{3, 5, 6, 7, 9} mean, median, range = 6

{4, 6, 8, 10, 12} mean, median, range = 8

{4, 5, 8, 11, 12} mean, median, range = 8

{5, 8, 10, 12, 15} mean, median, range = 10

{6, 8, 12, 16, 20} mean, median, range = 12

{7, 8, 13, 17, 20} mean, median, range = 13

{6, 11, 14, 19, 20} mean, median, range = 14

{2, 3, 4, 5, 6} mean, median, range = 4

{3, 4, 6, 8, 9 } mean, median, range = 6

{3, 5, 6, 7, 9} mean, median, range = 6

{4, 6, 8, 10, 12} mean, median, range = 8

{4, 5, 8, 11, 12} mean, median, range = 8

{5, 8, 10, 12, 15} mean, median, range = 10

{6, 8, 12, 16, 20} mean, median, range = 12

{7, 8, 13, 17, 20} mean, median, range = 13

{6, 11, 14, 19, 20} mean, median, range = 14

Source: Eric Berchtold and Melissa Minnix

I had a student come up with 2, 3, 4, 5, 6.

Thanks. I added this to the answer.

Additional solutions:

{4, 6, 8, 10, 12} mean, median, range = 8

{7, 8, 13, 17, 20} mean, median, range = 13

{6, 11, 14, 19, 20} mean, median, range = 14

{4, 5, 8, 11, 12} mean, median, range = 8

{3, 4, 6, 8, 9 } mean, median, range = 6

{6, 8, 12, 16, 20} mean, median, range = 12

{3, 5, 6, 7, 9} mean, median, range = 6

Thanks Eric and Dan for the extra solution sets.

Additional solutions:

{4, 5, 7, 8, 11} mean, median, range = 7

{4, 7, 8, 9, 12} mean, median, range = 8

{6, 12, 13, 15, 19} mean, median, range = 13

{5, 9, 10, 11, 15} mean, median, range = 10

One of the answers included is incorrect.

{6, 8, 12, 16, 20} mean= 12.4 median= 12 range= 14

The problem does not state that the whole numbers need to be unique whole numbers, so can a set include a mode? The set {3,3,5,6,8} contains 5 whole numbers whose mean, median, and range are 5.

I don’t see why not Tracey. That would be an interesting addition. I think the only reason it is not mentioned is because mode is not a Common Core State Standard.

Nrich has a similar problem set which includes mode if some want to include it: https://nrich.maths.org/11281

2 plus 2 is 4 minus 1 is three quick maths

My students found the following:

6,7,10,11,16

2,4,5,7,7

5,15,15,20,20

5,6,10,14,15

4,9,10,13,14

5,7,10,13,15

4,8,9,11,13