If the positive integers 15,9,5,7 and x have a mean and median that are identical, what is the value of x?

Question

I don't know where to start with this problem.

Answer 1

Hi David,

 

The mean is the sum of the integers divided by the number of integers: (15+9+5+7+x)/5 = (36+x)/5

 

The median is halfway between the minimum and maximum integers (let's assume that x falls between 5 and 15):(5+15)/2 = 10

 

So 10 = (36+x)/5

 

Cross multiply: 50 = 36+x

 

Subtract 36 from both sides: 14 = x