by Robin Nayler
Five people take part in a run to a distant point a whole number of metres away and then back to the starting point.
The out and return legs are run at constant speeds with the speeds on the outward leg all being a whole number of centimetres per minute.
The first runner runs both legs at the same speed but the second to the fifth runners increase their speeds on their return legs by 10%, 20%, 30% and 40% respectively.
They all finish at the same time, taking a whole number of minutes a little less than half an hour.
What is the total length of the race in metres?