Four projects P, Q, R and S, are available to a company which is facing shortages of capital over the next years but expects capital to be freely available thereafter.

	P 000	Q '000	R 000	S 000
Total capital required over life of project	20	30	40	50
Capital required in next year	20	10	30	40
Net present value (NPV) of project at companys cost of capital	60	40	80	80

In what sequence should the projects be selected if the company wishes to maximise net present values?