My Answer: 861.33 KB
Explanation:
Use small k = 1000 and capital K = 1024.
Given sample frequency = 44.1 kHz = 44.1 * 1000 = 44100 bits per second
This is stereo audio signal, it will need 2 channels.
While converting to MP3 it will need 16 bits to represent 1 sound signal.
So, Bit Rate = 2 * 16 * 44100 = 1411200 bps
Given compression ratio = 0.5
Compressed Bit Rate will be = 705600 bps
For 10 seconds, data will be = 7056000 bits = 882000 Bytes = (861.33 * 1024) Bytes = 861.33 KB
Reference: http://www.theaudioarchive.com/TAA_Resources_File_Size.htm