Puzzle ZZLD 

Workings

Hint
There are three feet in a yard, and 1,760 yards in a mile.

Answer
Seconds in a week.

Reasoning
There are 60 x 60 x 24 x 7 = 604,800 seconds in a week.

There are 3 x 1760 x 100 = 528,000 feet in 100 miles.