Please forgive me if I have this in the wrong forum, but I am 'stuck' my 12yr old daughter came to me with this & I want to run & hide..
Avg. of 4#'s is 27
Avg. of 3#'s is 31
What is the 4th #?
Any help seriously appreciated
call your 4 numbers:
the average of these numbers is
but you have the answer to this
i.e.
=> multiplying across by the you get:
if it's the same set of numbers,
then the average of these is
you also have the answer to this
i.e.
=> multiplying across by the you get:
so therefore must be:
Excellent! believe it or not that's what I did; 108 - 93
but being honest I had no idea why I was submitting 15,
Now that you have explained, thank you very very much
maybe my daughter will not look at me as a 'd'oh...(well probably asking too much there!)