Puzzle ZBWI 

Workings

Hint
Light travels over 186,000 miles each second.

Answer
Miles travelled by light in a second.

Reasoning
Light travels over 186,000 miles per second.

There are 2.54cm in an inch, 12 inches in a foot, 3 feet in a yard, and 1760 yards in a mile. So there are 2.54 x 12 x 3 x 1760 = 160,934.4cm in a mile.