Answer: Number of sociology books sold = 143 books
Number of physics books sold = 143 + 45 = 188 books
Explanation:
Let us take the number of sociology books sold = x
Number of physics books sold = x+45
So now we can form an equation
x+x+45 = 331
2x+45 = 331
2x = 331-45
2x = 286
x = 286 รท 2
x = 143