Difference between revisions of "1959 AHSME Problems/Problem 19"

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== Problem ==
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With the use of three different weights, namely <math>1</math> lb., <math>3</math> lb., and <math>9</math> lb., how many objects of different weights can be weighed, if the objects is to be weighed and the given weights may be placed in either pan of the scale? <math>\textbf{(A)}\ 15 \qquad\textbf{(B)}\ 13\qquad\textbf{(C)}\ 11\qquad\textbf{(D)}\ 9\qquad\textbf{(E)}\ 7</math>
 
With the use of three different weights, namely <math>1</math> lb., <math>3</math> lb., and <math>9</math> lb., how many objects of different weights can be weighed, if the objects is to be weighed and the given weights may be placed in either pan of the scale? <math>\textbf{(A)}\ 15 \qquad\textbf{(B)}\ 13\qquad\textbf{(C)}\ 11\qquad\textbf{(D)}\ 9\qquad\textbf{(E)}\ 7</math>
  
 
== Solution ==
 
== Solution ==
  
The heaviest object that could be weighed with this set weighs <math>1 + 3 + 9 = 13</math> lb., and we can weigh any positive integer weight at most that. This means that <math>13</math> different objects could be weighed, so our answer is <math>boxed{\textbf{(B)}}</math> and we are done.
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The heaviest object that could be weighed with this set weighs <math>1 + 3 + 9 = 13</math> lb., and we can weigh any positive integer weight at most that. This means that <math>13</math> different objects could be weighed, so our answer is <math>\boxed{\textbf{(B)}}</math> and we are done.
  
 
== See also ==
 
== See also ==

Latest revision as of 12:59, 16 July 2024

Problem

With the use of three different weights, namely $1$ lb., $3$ lb., and $9$ lb., how many objects of different weights can be weighed, if the objects is to be weighed and the given weights may be placed in either pan of the scale? $\textbf{(A)}\ 15 \qquad\textbf{(B)}\ 13\qquad\textbf{(C)}\ 11\qquad\textbf{(D)}\ 9\qquad\textbf{(E)}\ 7$

Solution

The heaviest object that could be weighed with this set weighs $1 + 3 + 9 = 13$ lb., and we can weigh any positive integer weight at most that. This means that $13$ different objects could be weighed, so our answer is $\boxed{\textbf{(B)}}$ and we are done.

See also

1959 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 18
Followed by
Problem 20
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All AHSME Problems and Solutions

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