Two roadway designs are under consideration for access to a permanent suspension bridge. Design 1A will cost $1.7 million to build and $175,000 per year to maintain. Design 1B will cost $3.6 million to build and $40,000 per year to maintain. Both designs are assumed to be permanent. Use an AW-based rate of return equation to determine (a) the breakeven ROR and (b) which design is preferred at an MARR of 25% per year.

Answer and Explanation:

A. Given that Design 1A will cost $1.7 million to build and $175,000 per year to maintain

Given that Design 1B will cost $3.6 million to build and $40,000 per year to maintain

Both designs are assumed to be permanent

To find ROR using AW based rate of return equation, we find present value of each design and equate them:

Each design is permanent so

Present value of perpetuity:

Design 1A= 1700000+175000/r

Design 1B = 3600000+40000/r

=1700000+175000/r=3600000+40000/r

135000/r=1900000

Cross multiply

r=135000/1900000

r= 0.0710

r=7.10%

B Given that ROR=7.10% and MARR is 25%

MARR>ROR

Hence we reject both designs

answer: a. the kind of population living in your neighbourhood.

the census explorer data tool by the us census bureau allows the user to zoom in on any neighbourhood within the united states and find the kind of people residing in that by race and age.  

the tool needs to needs to be used twice – once in order to find what type of people reside in a neighbourhood, and then to see the age groups of the people in the same neighbourhood.