Answer:
The answer is below
Step-by-step explanation:
a)
The present cost of design 1A = 2700000 + 175000/r
The present cost of design 1B = 3800000 + 40000/r
Where r is the rate of return.
At breakeven rate of return, the present cost of both designs would be the same. Hence:
2700000 + 175000/r = 3800000 + 40000/r
3800000 - 2700000 = 175000/r - 40000/r
1100000 = 135000/r
r = 135000 / 1100000 = 0.1227
r = 12.27%
Therefore the breakeven rate of return is 12.27%
b) At an MARR of 10% per year, that is r = 0.1:
The present cost of design 1A = 2700000 + 175000/0.1 = $4.45 million
The present cost of design 1B = 3800000 + 40000/0.1 = $4.2 million
At an MARR of 10% per year, design 1B Correct is preferred because it has the lowest cost.