Iam a mutiple of 60. i am between 400 and 600 . i am 40 away from a multiple of 100. who am i

There is no possible answer. 
The #s are 420, 480, and 540.
None of them are 40 away from a multiple of 100.
However, it is was between 300 and 600, the answer would be 360.

Hey dear, hoping i'll be