Question

The mean of 5,x,10,6,12 is 9. Find x

Answer 1

x = 12

Explanation:

The mean calculated by adding all the numbers of a set and dividing it by the total number of numbers. In this case, we have five numbers, but we do not know what the sum of all the numbers is because one of the numbers in under the pronumeral x. The find this out we need to work backwards. We know that when all the five numbers are added we should get 45 (it is 9 time 5 as there are five numbers in the set). The next step is to subtract 45 from the number that we known (i.e. 45 - 5 - 10 - 6 - 12). This comes to 12.

To double-check if you got the right answer you could add all five numbers include the 12 and divide it by 5 to see if the answer is 9.

Answer 2

12

Solution,

Summation FX= 5+10+6+12+X

=33+x

N(total no.of items)=5

Now,

Mean= summation FX/N

or 9=33+X/5

or 9*5=33+X ( cross multiplication)

or 45=33+X

or -x=33-45

or -x=-12

X=12

Hope this helps...

Good luck on your assignment..