Logical Interview Question:

Seventy five years ago pharmacists weighed medicine on balances like the ones you have been using. The mass pieces were very expensive, so a pharmacist would buy as few mass pieces as possible. If a pharmacist had 1-g, 3-g, and 9-g mass pieces, he or she could weight out any number of grams from 1 g to 13 g. Show how could measure all of the masses from 1 g to 13 g using only the three mass pieces given?

Submitted by: Administrator

Ya,he can measure..
Initially 2 gm will be calculated by taking 3 gm and removing 1 gm using 1 gm mass..Then similarly,
2=3gm-1gm
4=3gm+1gm
5=9gm-(3gm+1gm)
6=9gm-3gm
7=(9gm+1gm)-3gm
8=9gm-1gm
10=9gm+1gm
11=(9gm+3gm)-1gm
12=9gm+3gm
13=9gm+3gm+1gm

Thus he can measure from 1-13 gms
Submitted by: Administrator