Every 30 minutes a bus leaves from Gorakhpur bus station to Gonda. A person goes to the inquiry counter and inquiries about the next bus and gets to know that the next bus will leave after 15 minutes. If it is 10:05 now, what time did the last bus leave?
1
10 : 10
2
9 : 50
3
9 : 45
4
10 : 20