Based on estimates the data for two types of bridges with different lives are as follows.

	Timber bridge	Steel bridge
First cost	P10,000,000	P28,000,000
Salvage value	400,000	1,000,000
Life in years	12	36
Annual maintenance	1,200,000	500,000

If minimum rate attractive of return is 9%, determine which project is more desirable using:

1. ROR method
2. AC method
3. PWC method