Subject: mathqa
Question: the average of 10 consecutive integers is 15 . then , 9 is deducted from the first consecutive number , 8 is deducted from the second , 7 is deducted form the third , and so on until the last number which remains unchanged . what is the new average ?
Option: 
A: 10.5
B: 11
C: 12
D: 11.5
Answer: A