Posted by Stephanie on Friday, September 5, 2008 at 7:28pm.
A man selling fruit has only three weights. But with them he can weigh any whole number of kilograms (from 1 kg to 13 kg) inclusive on his balance.
What weights does he have?
Responses
math  Kalyan, Friday, September 5, 2008 at 4:38am
The man had 1kg, 3kg and 9 kg weights.
How do you set it up to get this answer? Any ideas?

Math  drwls, Friday, September 5, 2008 at 7:42pm
You can prove to yourself that 1,3 and 9 work. With them, you can form counterbalances of
1, 2 (31), 3, 4 (3+1), 5 (913),6 (93), 7 (9+13), 8 (91), 10 (9+1), 11 (9+31), 12 (9+3) and 13 (9+3+1)
A minus sign means putting the weight on the same side of the balance as the weighed object.
Proving that other combinations will not work is harder, but is not necessary.
Answer This Question
Related Questions
 math  A man selling fruit has only three weights. But with them he can weigh ...
 algebra  A man selling fruit has only three weights; but with them he can weigh...
 math  ou have only four weights and a balance scale. If your task is to weigh ...
 Math  An apothecary has a set of five weights for use in the pans of his ...
 UNM  Suppose that the average weight of students in a statistics class is 75.5 ...
 Physics  At the gym, a woman lifts 40 kilograms of weights on the leg press ...
 statistics  .) A hospital in a large city records the weight of every infant ...
 calculus  The chemistry teacher at Stevenson High School is ordering equipment ...
 algebra  A shipping clerk wishes to determine the weights of each of the 4 ...
 Math  The sum of the weights of a dog and cat is 27 pounds. The dog weights an ...
More Related Questions