As a 100 yard dash sprinter in the 60's the average time would be about 10.2 to 10.3.
40 yard dash/10 yard dash= 4 What ever the time you got for the ten yard, you multiple it by 4. It could be an average of your running time per 10 yard dash. Sometimes for several runners, they would feel worn out by the time when reaching the 40 yard mark.
I am 13 and i am always the fastest kid on all the sports I play i run a 7.4 60 yard dash the average between 7.7-8.8
average time is 9.81 seconds
In the 4.4 range