ararom said:

the average of 3a+4 and another number is 2a. What is the average of the other number and a?

If you have two numbers, m & n, what is the

expression of average of those two numbers ? \(\displaystyle \frac{m+n}{2}\\)

Assume that the other number = x

What is the

expression for average of '

x' and

3a+4?

Equate the above to '2a' - and solve for 'x'

Now find the average for 'a' and 'x' (from the solution above)