7-2
2. Relationship between investment criteria.
The information given tells:
• Nothing about the discounted payback period
3. Net present value and payback period.
If the payback period is less than the economic life of the project, its net present value can be
either positive or negative. This is because the relevant cash flows in the computation of the
payback period are actual cash flows while those in the computation of the net present value are
discounted cash flows. The only certain case is the trivial case when the cost of capital of the
project is zero. In that case, the project’s net present value is, by definition, equal to zero at its
payback period. Since it lasts longer, its net present value is positive.
4. The internal rate of return of mutually exclusive projects.
a.
The intersection of Project A and Project B’s NPV lines represents the discount rate which
produces the same NPV for the two projects. Assuming the risk of each project is the same, and
the firm’s cost of capital is the discount rate at the intersection point, one should be indifferent
between the two projects.
d.
The choice depends on the cost of capital. When the cost of capital is lower than the break-even
rate (the point where the project NPV lines intersect), Project A is better, and Project B is better
when the cost of capital is higher than the break-even rate. Note that the choice between the two
projects cannot be made by comparing their internal rates of return because those rates have no
particular economic significance.