New buses for a mass-transit agency cost $10 million and are expected to last for 10 years with a $1 million salvage value. The buses cost $500,000 to operate and maintain each year. If the system is used for 624,318 trips per year, with the average cost to the rider of $1.50, but providing $4.00 in benefits, and the interest rate is 4% per year, the benefit-cost ratio using PW for the investment will be?