Difference between revisions of "2019 AMC 8 Problems/Problem 11"
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==Solution 2== | ==Solution 2== | ||
We have <math>70 + 54 = 124</math> people taking classes. However we over-counted the number of people who take both classes. If we subtract the original amount of people who take classes we get that <math>31</math> people took the two classes. To find the amount of people who took only math class web subtract the people who didn't take only one math class, so we get <math>70 - 31 = \boxed{\textbf{C} \, 39}</math> -fath2012 | We have <math>70 + 54 = 124</math> people taking classes. However we over-counted the number of people who take both classes. If we subtract the original amount of people who take classes we get that <math>31</math> people took the two classes. To find the amount of people who took only math class web subtract the people who didn't take only one math class, so we get <math>70 - 31 = \boxed{\textbf{C} \, 39}</math> -fath2012 | ||
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==Solution 3== | ==Solution 3== | ||
We're basically just finding the number of students not taking a foreign language since all the rest would be taking only math. $93-54= | We're basically just finding the number of students not taking a foreign language since all the rest would be taking only math. $93-54= | ||
Revision as of 10:03, 24 November 2019
Problem 11
The eighth grade class at Lincoln Middle School has 
students. Each student takes a math class or a foreign language class or both. There are 
eighth graders taking a math class, and there are 
eight graders taking a foreign language class. How many eighth graders take only a math class and not a foreign language class?
Solution 1
Let 
be the number of students taking both a math and a foreign language class.
By P-I-E, we get 
= .
Solving gives us 
.
But we want the number of students taking only a math class.
Which is 
.
~phoenixfire
Solution 2
We have 
people taking classes. However we over-counted the number of people who take both classes. If we subtract the original amount of people who take classes we get that 
people took the two classes. To find the amount of people who took only math class web subtract the people who didn't take only one math class, so we get 
-fath2012
Solution 3
We're basically just finding the number of students not taking a foreign language since all the rest would be taking only math. $93-54=
See Also
| 2019 AMC 8 (Problems • Answer Key • Resources) | ||
| 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. 
