Answer
$47000$ hairs
Work Step by Step
We know that we lose $100$ hairs per day. To find the number of hairs lost in $2$ years, we multiply by the number of days in a year (365) and the number of years (2):
$100~hairs/day*365~days/year*2~years=36500*2=73000$ hairs
Since we started with $120000$ hairs, we find the number remaining by subtraction:
$hairs~left=120000-73000=47000$ hairs
