A certain number of workers can do a work in 85 days. If there were 10 workers more it could be finished in 10 days less. How many workers are there?
Select.
A) 75 B) 30 C) 28 D) 24 E) 32

Rationale: "number of workers = 10 * ( 85 - 10 ) / 10 = 75 answer is a"
Answer: A