BrainBashers - Random Puzzles

Puzzle 57

Yesterday I was asked to buy some stamps.

In the land of BrainBashers, stamps are available in denominations of 4p, 5p, 7p, 12p, and 19p (just the five different values).

For three denominations of stamps, I was asked to buy six of each. For the other two denominations. I was asked to buy ten of each.

Unfortunately, I forgot which I was supposed to buy six of, and which to buy ten of!

Luckily I had been given the exact money required to buy the stamps, £3.50, so the shopkeeper was able to work out the stamps I needed.

Which stamps did I have to buy?

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Puzzle 58

How many squares of any size on this chessboard do not contain a rook?

Rooks On A7, C2, E4

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Puzzle 59

A large freshwater reservoir has two types of drainage system. Small pipes and large pipes.

6 large pipes, on their own, can drain the reservoir in 12 hours.

6 small pipes, on their own, can drain the reservoir in 18 hours.

How long will 6 large pipes and 6 small pipes take to drain the reservoir?

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Puzzle 60

This BrainBashers safe has a rather unusual control panel.

In order to open the safe, you have to press every single square once only, in the correct sequence, ending on the square marked E.

Each square indicates which square to press next, for example, 2U means move up 2 squares and 3R means move right 3 squares.

Can you determine which square you must start with?

Note: this puzzle is not interactive, and the safe buttons cannot be clicked.

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