Question

Can someone show me how they got these numbers, show all the work please, thank you. Correct answers are shown in picture.

A bridge is to be constructed now as part of a new road. Engineers have determined that current traffic volume on the new road wil stfly a two-lane road and a bridge at the present time. Because of the uncertainty regarding future traffic, the time at which the I two lanes will be required is currently being studied Two alternatives are being considered Alternative 1 -One-stage construction: Build a four lane bridge right now for $379,000 ge construction Start with a two-lane bridgé now for $160,000 and widen to four lanes later when traffic justifies. The future cost of widening the bridge to four-lanes at that time will be $160.000 plus an extra $28,000 for every year that widening s delayed For example, i future widening is done at the end of year 4 the cost of widening at that time will be equal to The following estimates have been made of when widening to a four-lane bridge will be $160,000 + 4x($28.000)-$272000. required Pessimistic estimate Most likely estimate End of year2 End of year 4 (a) Calculate the PW of costs for the different scenarios of Alternative 2 , PWpessimistic (6%)-S-352 2thousand [Round to one decimal place ) PWmost likely (6%) t s-375.5. thousand (Round to one decimal place ) PWoptimistic(696)-s-4039, thousand (Round to one decimal place.) (b) Calculate the expected PW costs of Alternative 2 using the three-point estimation technique Expected PW s-376.4 thousand (Round to one decimal place.) (c) Based on these estimates, which alternative is more economical? A. Alternative 2 ХВ. Alternative 1 required Pessimistic estimate Most likely estimate Optimistic estimate End of year2 End of year 4 End of year 9 view of these estimates, which alternative would you recommend? The MARR used by the highway department is 6% per year

Answer 1

2- 2, 23G. 23 hant れしに。

2.2 S 8