Let (x+y)/2 = z {"original average of two numbers"} ----- eqn-1
according to first condition (2x+y)/2 = z+20 ------- eqn-2
then according to second condition (x+2y)/2 = z+25 -----eqn-3
solve both eqn 2 & 3 and you will find x+y = (4z/3)+30
arrange the result as eqn-1 to find original average of two numbers
(x+y)/2 = (2z/3)+15 ----- eqn-4
compare eqn-1 & 4 i.e
z = (2z/3)+15
by solving it, the result will be 45.
Were did 38 come from