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.
??
Puzzle 2
A farmer buys chicken feed for 47c per tonne, pig feed for $1.23 per tonne and cattle feed for $1.44 per tonne. The feed can only be purchased by the tonne, and part tonnes aren't sold.
How much of each would they have if they bought 100 tonnes for $100?
Reasoning
Each of the other words remains a real word if you remove the first and last letter: s-event-yb-raw-lc-love-rp-rope-rc-arro-t *s-win-ge-merge-dc-raft-yt-rave-ls-acre-ds-ton-ep-lung-e
??
Puzzle 4
This arrow is currently pointing from South to North.
Move one line and add one other to leave the arrow pointing from East to West.