Hint
How many reservoirs can each drain in 36 hours?
Answer
7 hours and 12 minutes.
Reasoning
We can use a time that 12 hours and 18 hours both fit in to, in 36 hours:
6 large pipes can drain 3 reservoirs.
6 small pipes can drain 2 reservoirs.
Therefore, together, 6 large and 6 small pipes can drain 5 reservoirs.
36 hours ÷ 5 = 7.2 hours for one reservoir.
7.2 hours = 7 hours and 12 minutes for one reservoir.
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Puzzle 3
How many squares, of any size, can be found on a standard chessboard? How many rectangles, of any size, can be found on a standard chessboard?
Remember when counting the rectangles, that squares are also rectangles.
Take the first letter of the second word
+ the first letter of the first word
+ the second letter of the first word
+ the last letter of the second word.
