Lou Barlow, a divisional manager for Sage Company, has an opportunity to manufacture and sell one of two new products for a five-year period. His annual pay raises are determined by his divisions return on investment (ROI), which has exceeded 25% each of the last three years. He has computed the cost and revenue estimates for each product as follows:

	Product A			Product B
Initial investment:
Cost of equipment (zero salvage value)	$	340,000		$	540,000
Annual revenues and costs:
Sales revenues	$	390,000		$	490,000
Variable expenses	$	176,000		$	226,000
Depreciation expense	$	68,000		$	108,000
Fixed out-of-pocket operating costs	$	84,000		$	64,000

The companys discount rate is 18%.

Click here to view Exhibit 14B-1 and Exhibit 14B-2, to determine the appropriate discount factor using tables.

Required:

1. Calculate the payback period for each product.

2. Calculate the net present value for each product.

3. Calculate the internal rate of return for each product.

4. Calculate the profitability index for each product.

5. Calculate the simple rate of return for each product.

6a. For each measure, identify whether Product A or Product B is preferred.

6b. Based on the simple rate of return, which of the two products should Lous division accept?

I need help with part 3. if you could please explain how to calculate the internal rate of return?