P P P U U Z Z Z Z Z L L L L E S S gives 3 x P, 2 x U, 5 x Z, 4 x Z (only 4 as we've already used one), 4 x L, 1 x E, 2 x S.
3 * 2 * 5 * 4 * 4 * 1 * 2 = 960.
Traffic was bad going to work this morning. I only managed to average 30 mph.
How fast must I go home tonight, along the same route, to average 60 mph for the entire round trip?
Direct Link: www.brainbashers.com?ZNID
Hint: It doesn't matter what the distance is, so try a random distance.
Answer: This cannot be done.
It does not matter how far the trip is, let's assume that it is random distance, say 60 miles, and remembering that Time = Distance ÷ Speed.
The morning trip took 60 miles ÷ 30 mph = 2 hours.
To average the required 60 mph, we would have to travel the total distance (of 120 miles) in 2 hours. However, we've already used all of the two hours for the morning trip!
Choosing any random distance would also show that it can't be done.