How many consecutive zeros are there at the end of the number 105! (105 factorial)?
Solution to yesterday’s problem:
If three of Kelly’s blocks makes a half mile, then one of those blocks must be one-sixth of a mile. Kelly can walk one-sixth of a mile in twenty minutes (admittedly slow, maybe she socializes). Logically this proportion works out to one mile in 120 minutes, or two hours.
Two of her friend’s blocks make up a mile, so one of those blocks is a half mile. Using the proportion from above, 1 mile per 2 hours, we reason that 1/2 mile will take Kelly 1 hour to walk.