We have four numbers 103,107,113 and 120 .
The number of numbers is n = 4.
The sum of the numbers is S = 103 + 107 + 113 + 120
S = 210 + 233
S = 443
The average value of the 4 numbers is given by their sum divided by the number of numbers,
av = S/n
av = 443/4 = 110.75
Answer: average is 110.75