You own a coal mining company and are considering opening a new mine. The mine will cost $120 million to open. If this money is spent immediately, the mine will generate $20 million for the next 10 years. After that, the coal will run out and the site must be cleaned and maintained at environmental standards. The cleaning and maintenance are expected to cost $2 million per year in perpetuity. What does the IRR rule say about whether you should accept this opportunity

B. There are two IRRs so you cannot use the IRR as a criterion for accepting the opportunity.

Explanation:

The Internal Rate of Return can be useful in capital budgeting to enable a company know if an investment will be profitable. It is defined as the discount rate that causes the Net Present Value(NPV) to be zero. If the IRR is greater than the required return then the project should be accepted as it will have a profitable NPV.

IRR has some problems however and one of them is reflected here. There can sometimes be two IRRs and when this happens, using IRR as a viability measure cannot be done because a single rate is needed for comparison with the required return.

there is no following so id just amuse false

b. take periodic breaks and alternate between tasks.  

will increase work efficiency, and avoid health issues.