The average of these numbers is nine tenths,

, or .9, however you would like to put it.
You need to show us the figure so we can tell you.
The numbers that would be smaller would be the two with the difference of 26.
27-1=26 where as, if you were to use a 1 in each, 99+1= 100. Therefore 27 and 1 (28) is less than 99 and 1 (100).
Hey there,
solving for a is just like you think of all other letter as a constant
i.e the only variable is a
so you need to subtract b as a start
d=a+b-c/3
-b -b
=============
-b+d=a-c/3 now it's time to add c/3 (isolate a by itself in one side)
-b+d=a-c/3
+c/3 +c/3
==============
c/3-b+d=a
Hence you have solved for a