Answer: Yes they Should.
Step-by-step explanation:
Should Chen buy the new machine is dependent on the Net Present Value of buying it. That is, over it's useful life, will it bring in cash flows that will cover discounted the outflows.
The cash flow of $18,300 is AFTER TAX so no need to worry about the given Marginal rate there.
Because the cash flows are even, we can use the Present Value of an Annuity formula which is,
PV = P( 1 -( (1+r)^ -n )/ r)
Where,
P is payment / cash flow
r is rate(WACC in this case)
n is the number of periods
Meaning the NPV formula will be,
= -Initial outflows + present value of inflows
= -104,000 + (P( 1 -( (1+r)^ -n )/ r))
= -104,000 + ( 18,300 ( 1 - ( 1 + 0.1) ^ 10)/0.01))
= - 104,000 + 112,445.58
= $8,445.58
$8,445.58 is the NPV they would gain from getting the New Machine.
Chen SHOULD buy the machine.