The average /mean of five numbers is 13.Four of the numbers are:11,9,15 and 26.what is the fifth number?

Question

I do not know what to do

 

Answer 1

  Hi Christy...lkets try this....    To get an idea the question says   five numbers,

 

           and the mean (average)   is 13   so  multiply 13 times 5  =65

 

           Now add these numbers:

 

                            11

                              9

                            15

                            26

                          ____

                         =61        ----and 13 x 5 =65

 

                                       Now subtract 65 -61  = 4  -->  missing number

 

                                       Now we add  4 to the list

 

                           4

                          11

                            9

                         15

                          26

                        ____

                        =65   --->  Now we have 5 numbers, the numbers are small and so is the total

 

 

                                           Now divide  65  by 5    =13   -----> Average/mean

 

 

                             Hope this helps!

 

                                2/29/16

 

                                

Answer 2

Hi Christy,

 

 

The average /mean of five numbers is 13.Four of the numbers are:11,9,15 and 26.what is the fifth number?

 

To find an average you add up all the values and divide by the number of values.

 

The equation is:    

Let x=the fifth number

 

(11+9+15+26+x)/5 =13

 

Simplify the numerator:  (61+x)/5 = 13

Cross multiply:               61+x=5(13)

Simplify                         61+x=65

Add -61 to both sides:        x=65+-61

simplify                              x=4

 

ANSWER:  The fifth number is 4.