Mental Floss

Brain Game: Weighing Chuck


Good luck with today's Friday Free-for-all challenge here at the Brain Game.

Using an old-style balancing scale, Chuck wants to be able to discern any weight from from 1 to 30 lbs (to the nearest pound) using the fewest number of counterweights with the lightest total weight.

Given this information, find the fewest number of counterweights that Chuck would need, and the weight of each of them.

Here is the SOLUTION.


Chuck would need a minimum of FOUR weights. Either of these combos work:

(A) 1-lb. (B) 3-lb. (C) 7-lb. (D) 19-lb.

(A) 1-lb. (B) 3-lb. (C) 9-lb. (D) 17-lb.

Chuck could then discern weights by placing the counterweights on one or both sides of the scale, along with the object being weighed.

Thanks for playing!