Difference between revisions of "1988 AHSME Problems/Problem 10"

(Solution)
(Solution)
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This rounds to <math>2.4</math>If they subtracted, we have:
 
This rounds to <math>2.4</math>If they subtracted, we have:
 
<cmath>2.43865-0.00312=2.43553.</cmath>
 
<cmath>2.43865-0.00312=2.43553.</cmath>
This rounds to <math>2.4</math>. Therefore, we have the answer to be <math>\fbox{\textbf{(D) 2.4}}</math>
+
This rounds to <math>2.4</math>. Therefore, we have the answer to be <math>\fbox{\textbf{(D)} 2.4}</math>.
  
 
== See also ==
 
== See also ==

Revision as of 19:25, 18 May 2016

Problem

In an experiment, a scientific constant $C$ is determined to be $2.43865$ with an error of at most $\pm 0.00312$. The experimenter wishes to announce a value for $C$ in which every digit is significant. That is, whatever $C$ is, the announced value must be the correct result when $C$ is rounded to that number of digits. The most accurate value the experimenter can announce for $C$ is

$\textbf{(A)}\ 2\qquad \textbf{(B)}\ 2.4\qquad \textbf{(C)}\ 2.43\qquad \textbf{(D)}\ 2.44\qquad \textbf{(E)}\ 2.439$

Solution

If added together, we have: \[2.43865+0.00312=2.44177\] This rounds to $2.4$If they subtracted, we have: \[2.43865-0.00312=2.43553.\] This rounds to $2.4$. Therefore, we have the answer to be $\fbox{\textbf{(D)} 2.4}$.

See also

1988 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 9
Followed by
Problem 11
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
All AHSME Problems and Solutions

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