Answer:
Assuming this is 0 based array indexing, it would look like this...
[ 5, 6, 10, 7, 3, 2.5 ]
[ 0, 1, 2, 3, 4, 5, 6 ]
The index of 7 would be 3.
The answer is projectile. Handguns and rifles use a cartridge having a single projectile or bullet. Shotguns use a shot shell comprising either a single bullet or a big number of small projectiles (shot or pellets). Though, the basic components of cartridges and shot shells are alike.
If you mean speakers. You should remove them or if you mean the speakers in the PC. Perhaps you put the headphones in the wrong one. Theres usually too one in the front and the other one in the back of the desktop.
Hope this helps.
Regards. Shaggy
Enjoy your music!