Let
x-------> the sum of the 4 numbers in the average 1
y-------> the sum of the 6 numbers in the average 2
we know that
x/4=20----------> x=20*4=80
y/6=74----------> y=6*74=444
so
The average of the 10 numbers is equal to
(x+y)/10=(444+80)/10----------> 52.4
therefore
the answer is
the average of the 10 numbers is 52.4