I think the answer would be true
To answer this problem, one way is to use the calculator and add directly the two numbers and get the average between the two. The answer is 25/77. We can also get this number by getting the LCM of the denominators which is 77. 2/7 is equal to 22/77 while 4/11 is equal to 28/77. 0.5*(22 +28) is equal to 25. Hence the answer is 25/77.
There might be a variety of averages for the 12 boys.
First set it up like this:

<span>then add a zero on to the 18 and a decimal point like this: </span>

then solve for 180/32 and add a decimal in the same location that it is in the 18.0 Hope this helps!