perplexus.info :: Weights and Scales : Faulty Scales

Faulty Scales (Posted on 2004-05-23)

Good scales have equal arms (arms are the the things that connect the actual scale to the center), but in one grocery stall, the arms of the scale are not equal. Pending replacement, the manager wonders if he can give correct weight this way:

"I'll balance a 1-pound weight on the left with sugar on the right, and then I'll balance the 1-pound weight on the right with some more sugar on the left, and the sugar will add up to exactly 2 pounds."

Will it? What are other (assuming that the above works, it may not) ways of weighing 2 pounds of sugar, if you also have a lead shot with you to help weigh? (Note and hint: The lead shot has an unknown weight. You can make it whatever weight you choose. Remember, the arms aren't equal, and you need 2 pounds of sugar.)

Submitted by Victor Zapana

Rating: 4.2500 (4 votes)

Solution: (Hide)

Th total weight of the sugar must be greater than 2.
To get proper weighing from faulty scales, the sugar and weights must be on the same side of the scales! Well, not exactly, but you can put the 1-pound weight on the left pan and balance it with lead shot on the right pan. Then remove the 1-pound weight on the left pan and balance it with lead shot on the right pan. Then remove the 1-pound weight and add sugar until it balances the lead shot. Do it twice and you have 2 pounds of sugar.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Solution	Iain	2004-05-25 14:12:43
Weighing in on this...	Brian Smith	2004-05-24 10:09:51
Easiest way.	Jer	2004-05-24 09:28:23
re: Grocery Store	Larry	2004-05-23 18:41:14
No Subject	Victor Zapana	2004-05-23 13:58:13
Error factor	Larry	2004-05-23 10:33:30
ways	Charlie	2004-05-23 10:25:21
First part	Larry	2004-05-23 10:08:35

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