For average of 2 numbers, you add them up and divide by two, so that means when you add them up, the sum should be 16*2=32, so one of the numbers is 11, so to find the other number subtract 11 from the sum, 32, 32-11=21
So we know one of the numbers is 11, so in order to get the average of 16, there needs to be a number that when added to 11 and divided by 2 gets you to 16. So let's put that into an equation. :)
16 = (11 + x) /2
We have to get x alone so we need to multiply the 2 to the left side.
32 = 11 + x
Now, to get x alone we have to subtract 11 from both sides.
