Answer:
0.005566 miles/sec
Explanation:
We are given that The record for Boston marathon is 1 hour and 18 minutes and 27 seconds.
The Boston marathon is 26.2 miles long.
So, Time = 1 hour 18 minutes 27 seconds
1 hour = 3600 seconds
1 min = 60 seconds
So, 18 min =

So, Time =( 3600+1080+27)seconds=4707 seconds
Distance = 26.2 miles
Speed =

Speed =

Speed =

Hence the average speed of record winner is 0.005566 miles/sec