A crocodile is stalking his prey located 20m further up a river, and on the other side. Crocodiles travel at different speeds on land and in water. The time taken for the crocodile to reach its prey can be minimised if it swims to a particular point “P” which is located “x” metres up river towards the prey, as shown.

The time taken “T” measured in tenths of a second is given by:


(a) Calculate the time taken if the crocodile does not travel on land.
(b) Calculate the time taken if the crocodile swims the shortest distance possible.
(c) Between these two extremes there is a value of “x” which minimises the time taken, find this value of “x” and hence the minimum possible time .


Go To >> Solution <<