Problem: 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 ?
Rationale: "number of workers = 10 * ( 85 - 10 ) / 10 = 75 answer is a"
annotated_formula: divide(multiply(subtract(85, 10), 10), subtract(85, subtract(85, 10)))