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Four vehicles travelled on a road with constant velocities. The car overtook the scooter at 12 o'clock, then met the bike at 14.00 and the motorcycle at 16.00. The motorcycle met the scooter at 17.00 then it overtook the bike at 18.00. At what time did the bike and the scooter meet?

### There and Back

Brian swims at twice the speed that a river is flowing, downstream from one moored boat to another and back again, taking 12 minutes altogether. How long would it have taken him in still water?

### Escalator

At Holborn underground station there is a very long escalator. Two people are in a hurry and so climb the escalator as it is moving upwards, thus adding their speed to that of the moving steps. ... How many steps are there on the escalator?

# Jumping Gerbils

##### Stage: 4 Challenge Level:

A strange scene : imagine a conveyer belt, with tins placed at regular intervals onto the belt at one end, moving along at a steady rate towards a labelling machine at the far end. A gerbil starts from a tin at the beginning of the belt and steadily jumps from tin to tin, finally jumping off immediately before the labelling machine.

When the gerbil jumps at a rate of one jump per second he arrives at the labelling machine in 20 jumps but if he speeds up and manages two jumps per second he can fit in 32 jumps before the end of the line.

How many tins are there on the line ?