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The average of six numbers is 6. If 3 is subtracted from each of four of the numbers, what is the new average?

 Jul 21, 2014

Best Answer 

 #5
avatar+98044 
+16

Nice answer, ND........here's my slightly different approach......

Let the sum of the six numbers = S

So

S/6 = 6

And if 3 is subtracted from each of four numbers, we have...

(S -12) / 6 =

S/6 - 12/6 =

6 - 2   = 4

 

 Jul 22, 2014
 #1
avatar+3450 
+13

The average of 6 numbers is 6. This means that all 6 numbers have to add up to 36.

It doesn't matter what the numbers are, but in order to average out to 6, the sum of all the numbers divided by 6 has to equal 6.

The only thing that gives 6 when divided by 6 is 36.

 

Now, 3 is subtracted from 4 numbers, for a total of 12.

(36-12)/6 tells us our new average

24/6

4 is the new average.

 Jul 21, 2014
 #2
avatar
+3

Thanks NinjaDevo!

 Jul 21, 2014
 #3
avatar+3450 
+8

Anytime!                  

 Jul 22, 2014
 #4
avatar+99122 
+8

You have given an excellent answer Ninja.  

Perhaps you would like to include it in your new sample questions thread. 

 Jul 22, 2014
 #5
avatar+98044 
+16
Best Answer

Nice answer, ND........here's my slightly different approach......

Let the sum of the six numbers = S

So

S/6 = 6

And if 3 is subtracted from each of four numbers, we have...

(S -12) / 6 =

S/6 - 12/6 =

6 - 2   = 4

 

CPhill Jul 22, 2014

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