Reasoning
At each stage, a new dot starts at the top. The first dot moves clockwise, the second dot moves counter-clockwise, the third dot moves clockwise, etc.
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Puzzle 18
I recently travelled from my home town to a distant music concert, on a pedal tricycle, of all things! My wonderful, three-wheeled tricycle.
I knew that the epic 2,345 miles would wreak havoc on the tyres, but luckily I took along 4 spares!
Instead of waiting for any single tyre to fail, I decided that I would rotate the tyres evenly, making sure that by the end of the trip, all seven tyres had travelled exactly the same distance.
Reasoning
A total of 2,345 miles were travelled and at any one time, three tyres were on the tricycle.
Therefore, 3 x 2,345 = 7,035 tyre miles were travelled, which was shared equally by the 7 tyres.
And 7,035 ÷ 7 = 1,005.
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Puzzle 19
I travelled from London to Glasgow last week at 60 miles per hour, I had filled my petrol tank just before I left, and it was full to the brim (25 gallons).
Unfortunately, my petrol tank sprang a leak immediately, and I only managed to drive 300 miles before I ran out of petrol.
My car does 30 miles per gallon, how fast was I losing petrol through the hole?
Hint
How much petrol was used for the journey itself?
Answer
3 gallons each hour.
Reasoning
I drove 300 miles at 30 miles per gallon, so I used 10 gallons. Which means I lost the other 15 gallons.
I drove the 300 miles at 60mph, which took me 5 hours.
So I lost 15 gallons of petrol in 5 hours = 3 gallons per hour.
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Puzzle 20
If a farmer buys chicken feed for 57c per tonne, pig feed for $1.52 per tonne and cattle feed for 43c per tonne. The feed can only be purchased by the tonne, and part tonnes aren't sold.
How much of each would he have if they had 100 tonnes for $100?
