Box I contains 30 cards numbered I to 30 and Box II contains 20 cards numbered 31 to 50. A box is selected at random and a card is drawn from it. The number on the card is found to be a non-prime number. The probability that the card was drawn from Box I is :

(1) $2\over3$

(2) $2\over5$

(3) $8\over17$

(4) $4\over17$

(1) $2\over3$

(2) $2\over5$

(3) $8\over17$

(4) $4\over17$