Question

Greene ran the 100-meter dash in 9.79 seconds. What was his speed in kilometers per hour (round to the nearest kilometer)?

Please explain the work behind the solution

Answer 1

`1m \ \ is\ \ (1)/(1000)km\\ 100m\ \ is\ \ (1)/(10)km\\ 1s\ \ is\ \ (1)/(3600)h\\ 9,79s\ \ is\ \ (9,79)/(3600)h\\\\ (100meters)/(9,79\ seconds)=(100)/(97)*((1)/(10))/((9,79)/(3600))=(100)/(97)*(1)/(10)*(3600)/(9,79)=(360000)/(970*9,79)=\\ (360000)/(9496,3)\approx\boxed{37,9(km)/(h)}`