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A long train, 440 yards long enters a tunnel that is 5 miles long.

The train is travelling at 35 miles per hour.

How long will train be in the tunnel, from the front of the train entering to the end of the train leaving?

[Ref: ZCTS]

Hint: Remember that 440 yards is 1÷4 of a mile.

Answer: 9 minutes.

The front of the train travels 5 miles, however, the rear has to travel the extra 0.25 mile, which is 5.25 miles in total.

At 35 mph this takes 5.25 ÷ 35 = 0.15 (of an hour).

0.15 x 60 = 9 minutes. QED.

Puzzle 2

What is represented by this BrainBat?

once
time

[Ref: ZAVO]

Hint: Say what you see.

Answer: Once upon a time.

Puzzle 3

What letter comes next in this sequence:

X L C D ==?==

[Ref: ZRYM]

Hint: Think of Italy.

Answer: M.

1000 in Roman numerals.

Puzzle 4

Bill and Ben takes turns flipping a coin. Whoever gets the head first is the winner.

If Bill has the first flip, what is the probability that he will win?

[Ref: ZHIP]

Hint: What is the probability of getting a head on the first toss?

Answer: 2/3.

The probability that he will get a head on his first toss is 1/2, if not, the probability he wins on his second toss is 1/2 + 1/8, etc. The sum of 1/2 + 1/8 + 1/32 + 1/128 = 2/3. QED

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