TMUA Viluxent Set 1 Paper 2 · Question 2

You have $n$ stacks of coins, each containing $n$ coins weighing $n$ grams each. However, one stack is defective, and every coin in that stack weighs only $n-1$ grams. You are given a scale that reports the exact total weight (in grams) of whatever is placed on it.

What is the minimum number of measurements needed to determine which stack is defective, for every $n\ge2$ ?

1

2

\lceil\log_2 n\rceil

n-1

n

FIt cannot always be determined

examday

Viluxent Set 1 Paper 2 · Q2