Assuming you can put Y for "yellow" in cell D6, type the following
formula in cell X6:

=IF(D6="Y",20,IF(C6D6,(C6-D6)*5,IF(C6<D6,(D6-C6)*10,"Equal")))

You do not specify what you want to happen when C6 = D6, so this
formula returns "Equal", but you can change this to what you want.

Pete