Problem: a group of men decided to do a work in 20 days , but 8 of them became absent . if the rest of the group did the work in 28 days , find the original number of men ?
Rationale: "original number of men = 8 * 28 / ( 28 - 20 ) = 28 answer is b"
annotated_formula: divide(multiply(8, 28), subtract(28, 20))