The company that I work for believes its latest project, which will
cost $80,000 to install, will generate a perpetual growing stream of
cash flows. Cash flow at the end of this year will be $5,000, and cash
flows in future years are expected to grow indefinitely at an annual
rate of 5 percent.

a. If the discount rate for this project is 10 percent, what is the project NPV?

b. What is the project IRR?

An excel spreadsheet would be great.  Thank you.

Regrettably, attaching an Excel spreadsheet is not possible via this
forum.  However, the calculations are very easy to understand, making
a spreadsheet superfluous.

First, we have a perpetuity with an initial payout of $5,000 with an
annual growth rate of 5%.

We know that the present value of such a perpetuity is equal to the
initial payout divided by the quantity (interest rate minus growth
rate).  In this case, this amounts to $5,000 divided by 0.05 or
$100,000.

To calculate the net present value, we subtract the $80,000
installation cost from the present value of the perpetuity.  This
results in a net present value of $20,000.

The internal rate of return is the interest rate that causes the net
present value to equal zero.  So, $5,000/(i-0.05) - $80,000 = 0. 
After performing some algebra, we learn that the internal rate of
return i is 11.25%.  Since the internal rate of return is higher than
the discount rate, we know that the net present value will be
positive, so everything checks out.

References:

Principles of Engineering Economy, eighth edition, Grant, Ireson, &
Leavenworth, John Wiley & Sons, 1990, page 101

Principles of Corporate Finance, fourth edition, Brealey & Myers,
McGraw-Hill Inc., 1991, page 34

Sincerely,

Wonko