When I use LOOKUP I get the value returned that I'm looking for. However,
I'm having problems also retrieving the value in the adjacent cell. For
example, lets say my lookup function is:

=LOOKUP(C15,A1:A20,B1:B20)

So, it takes the value in cell C15, finds the closest value in the the range
A1:A20 (lets say that value is found in A8), and then returns the value from
B8. How can I also get the value from B9?

Thanks.