there are 10 cig packs each conatining an unknown no of cigs( each =
pack has between 50 and 100). One pack has all bad cigs . Each good cig =(if u can agree that any cig is good) weighs 1gm. Each bad cig weighs =
1.1 gm or .99 gm but all bad cigs weigh same. Using a spring chemical =
balance ( which gives u the exactweight) .Find out which pack is bad , =
using the balance only once.