Problem: speed of a boat in standing water is 10 kmph and speed of the stream is 1.5 kmph . a man can rows to a place at a distance of 105 km and comes back to the starting point . the total time taken by him is ?
Rationale: "speed upstream = 8.5 kmph speed downstream = 11.5 kmph total time taken = 105 / 8.5 + 105 / 11.5 = 21.48 hours answer is b"
annotated_formula: add(multiply(add(add(10, 1.5), subtract(10, 1.5)), 105), multiply(subtract(add(divide(105, add(10, 1.5)), divide(105, subtract(10, 1.5))), add(add(10, 1.5), subtract(10, 1.5))), const_60))