11 Plus Exams Forum

Posted: **Fri Aug 20, 2010 6:01 pm**

Could anyone please help me on this question!!!!

The average 4 numbers is 10 1/2
If the average of 3 of them is 9 what is the 4th number????

Answer is 15

Posted: **Fri Aug 20, 2010 7:18 pm**

The average of 4 numbers is 10 1/2

So the total of the 4 numbers is 4x10.5 = 42

If the average of 3 of them is 9

So the total of the 3 numbers is 3x9 =27

42-27=15

Posted: **Fri Aug 20, 2010 9:21 pm**

mitasol thanks for the response

much appreciated!!!!

11 Plus Exams Forum

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