I believe the answer to this one is:
Take one pill out out of the first bottle, two pills out of the second bottle... etc. and weigh them all together. Then find out which bottle has the heavy pills by getting the total and finding the amount of the anomaly.
So if every bottle had 1.0g pills in it and the pills were added to the scale as described above, the total would be 210g. If the first bottle (the one we only used one pill for) had 1.1g pills, the total would be 210.1g. If the second bottle (two pills) had 1.1g pills, the total would be 210.2g... etc. all the way up to 212g.
To put it in (sort of) mathematical terms:
Bottle no. with heavy pills = (Weight - 210g) * 10
(Where bottle no. = amount of pills placed on scales)