Difference between revisions of "2008 AMC 8 Problems/Problem 11"

(Solution)
m (Undo revision 159793 by Raina0708 (talk) I messaged Raina0708 for the use of LaTeX. Deletion should not have been made.)
(Tag: Undo)
Line 9: Line 9:
  
 
==Solution==
 
==Solution==
The union of two sets is equal to the sum of each set minus their intersection. The number of students that have both a dog and a cat is 20+26-39 = A:7
+
The union of two sets is equal to the sum of each set minus their intersection. The number of students that have both a dog and a cat is <math>20+26-39 = \boxed{\textbf{(A)}\ 7}</math>.
  
 
==See Also==
 
==See Also==
 
{{AMC8 box|year=2008|num-b=10|num-a=12}}
 
{{AMC8 box|year=2008|num-b=10|num-a=12}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 18:22, 8 August 2021

Problem

Each of the $39$ students in the eighth grade at Lincoln Middle School has one dog or one cat or both a dog and a cat. Twenty students have a dog and $26$ students have a cat. How many students have both a dog and a cat?

$\textbf{(A)}\ 7\qquad \textbf{(B)}\ 13\qquad \textbf{(C)}\ 19\qquad \textbf{(D)}\ 39\qquad \textbf{(E)}\ 46$

Solution

The union of two sets is equal to the sum of each set minus their intersection. The number of students that have both a dog and a cat is $20+26-39 = \boxed{\textbf{(A)}\ 7}$.

See Also

2008 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 10
Followed by
Problem 12
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
All AJHSME/AMC 8 Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png