A minimarket store sells 2 types of instant noodles, Indomie at 20 packages and Japanese Ramen at 30 packages. Benny stopped at the minimarket one late night after working overtime and wanted to buy a supply of instant noodles for the week. He felt tired and wanted to return home as soon as possible so he didn’t pay attention to what type of instant noodle he bought. Benny purchased 10 packages of instant noodles from the minimarket and left for his home. 

What is the probability that Benny bought 6 Japanese Ramen? 

(Notes: Use 4 digits after decimal point)