Answer:
The present value of K is,
Step-by-step explanation:
Hi
First of all, we need to construct an equation system, so


Then we equalize both of them so we can find 

To solve it we can multiply
to obtain
, then we have
.
This leads to a third-grade polynomial
, after computing this expression, we find only one real root
.
Finally, we replace it in (1) or (2), let's do it in (1) 