The flight lasted for 12 seconds at an average speed of 10 feet per second. the ratio of the airplanes wingspan to the distance flown was 1: 3 what was the wingspan?

If the flight is 12 seconds at a rate of 10 ft/s. then the total distance is 120ft. therefore applying the ratio of wingspan:distance simply divide the distance, 120ft by 3, making your total wingspan 40ft

Where are the calculations?