possible
achievable
actable
answerable
applicable
ascertainable
attainable
banausic
capable of solution
compassable
decipherable
decodable
determinable
doable
effective
effectual
efficient
explainable
explicable
exploitable
feasible
manageable
maneuverable
manipulatable
negotiable
open to solution
operable
operatable
overcomable
performable
practicable
practical
pragmatic
realizable
resolvable
soluble
solvable
superable
surmountable
usable
viable
affordable
coherent
constructive
cost-effective
coöperative
credible
economical
empirical
innovative
intelligible
preconceived
reasonable
satisfactory
straightforward
sustainable
tenable
valid
unworkable