### Speedy Sidney

Two trains set off at the same time from each end of a single straight railway line. A very fast bee starts off in front of the first train and flies continuously back and forth between the two trains. How far does Sidney fly before he is squashed between the two trains?

### Illusion

A security camera, taking pictures each half a second, films a cyclist going by. In the film, the cyclist appears to go forward while the wheels appear to go backwards. Why?

### Walk and Ride

How far have these students walked by the time the teacher's car reaches them after their bus broke down?

# Thunder and Lightning

##### Stage: 3 Short Challenge Level:
See all short problems arranged by curriculum topic in the short problems collection

 Sound travels at about 330 metres per second; light travels so fast that it arrives almost instantaneously. If you time the gap between a flash of lightning and its clap of thunder as 6 seconds, roughly how far away is the storm?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.