If two integers x,y (x>y) are selected from -5 to 4(inclusive), how many cases are there?
A. 15
B. 18
C. 36
D. 45
E. 90
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If two integers x,y (x>y) are selected from -5 to 4(inclu
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- Max@Math Revolution
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There are 10 integers from -5 to 4 inclusive.Max@Math Revolution wrote:If two integers x,y (x>y) are selected from -5 to 4(inclusive), how many cases are there?
A. 15
B. 18
C. 36
D. 45
E. 90
Choose ANY 2 integers and make x = the larger integer and make y = the smaller integer.
Since the order in which we select the two numbers does not matter, we can use COMBINATIONS.
We can select 2 integers from 10 integers in 10C2 ways
10C2 = 45
Answer: D
RELATED VIDEOS:
Introduction to Combinations: https://www.gmatprepnow.com/module/gmat ... /video/787
Calculating Combinations in your head: https://www.gmatprepnow.com/module/gmat ... /video/789
Cheers,
Brent
- Max@Math Revolution
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10C2=45
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