If angle between vec(a) and vec(b) is (pi)/(3), then angle between 2bar(a) and -3vec(b) is

If angle between vec(a) and vec(b) is (pi)/(3), then angle between 2ba

1.	If angle between vec(a) and vec(b) is (pi)/(3), then angle between 2bar(a) and -3vec(b) is
Answer» `(PI)/(3)` `(2pi)/(3)` `(pi)/(6)` `(5PI)/(3)` ANSWER :C