Problem 3 A company needs a new grinder Compute the present
Problem 3: A company needs a new grinder. Compute the present worth for the mutually exclusive alternatives and identify which option is better. Assume an interest rate of 6% and that the grinder will be replaced with an identical model at the end of its life.
Option 1: Initial cost of $4500, annual costs of $300, salvage value of $500, life of 5 years
Option B: Initial cost of $5500, annual costs of $400, no salvage value, life of 10 years
Solution
Year
Option 1
Option 2
Discount Factor
Discounted Option 1
Discounted Option 2
0
-4500
-5500
1
-4500
-5500
1
-300
-400
0.9434
-283.02
-377.36
2
-300
-400
0.89
-267
-356
3
-300
-400
0.8396
-251.88
-335.84
4
-300
-400
0.7921
-237.63
-316.84
5
200
-400
0.7473
149.46
-298.92
6
-400
0.705
0
-282
7
-400
0.6651
0
-266.04
8
-400
0.6274
0
-250.96
9
-400
0.5919
0
-236.76
10
-400
0.5584
0
-223.36
PW
-5390.07
-8444.08
Discount factor = 1/(1+0.06)^n, n = number of years
Discounted Option 1 = Option1 values * Discount factor
Discounted Option 2 = Option2 values * Discount factor
Looking at the present worth value, option 1 is a better option as its present value is less and the company can save money
| Year | Option 1 | Option 2 | Discount Factor | Discounted Option 1 | Discounted Option 2 |
| 0 | -4500 | -5500 | 1 | -4500 | -5500 |
| 1 | -300 | -400 | 0.9434 | -283.02 | -377.36 |
| 2 | -300 | -400 | 0.89 | -267 | -356 |
| 3 | -300 | -400 | 0.8396 | -251.88 | -335.84 |
| 4 | -300 | -400 | 0.7921 | -237.63 | -316.84 |
| 5 | 200 | -400 | 0.7473 | 149.46 | -298.92 |
| 6 | -400 | 0.705 | 0 | -282 | |
| 7 | -400 | 0.6651 | 0 | -266.04 | |
| 8 | -400 | 0.6274 | 0 | -250.96 | |
| 9 | -400 | 0.5919 | 0 | -236.76 | |
| 10 | -400 | 0.5584 | 0 | -223.36 | |
| PW | -5390.07 | -8444.08 |


