i calculated the payback period in my coursework as follows:

Pay back= (Return for 10 years- total costs)
Capital cost

and my answer was :Pay back time = -3.4

the problem is i do not know exaxtly what this figure tells me and why.
It looks bad to me because it is a negative number which seems to imply that if carry on with my project i will not be able to payback the intial investment.
Am I right and why?
please help

nnm