Test 1, Section 7, Q23

GRE Quant Problem Solving
1

Hi

I need help in solving a question

GRE Big Book

Test 1, Section 7, Q23
After solving it multiple times, my answer is B (74), the book says D (31). Can anyone help please?

My email is aiman.haroon@gmail.com. Please reach out there.

Thanks,
Aiman