2007 AMC 8 Problems/Problem 19

Revision as of 19:36, 1 August 2021 by Raina0708 (talk | contribs) (Solution)

Problem

Pick two consecutive positive integers whose sum is less than $100$. Square both of those integers and then find the difference of the squares. Which of the following could be the difference?

$\mathrm{(A)}\ 2 \qquad \mathrm{(B)}\ 64 \qquad \mathrm{(C)}\ 79 \qquad \mathrm{(D)}\ 96 \qquad \mathrm{(E)}\ 131$

Solution

Let the smaller of the two numbers be x Then, the problem states that (x+1)+x<100. (x+1)^2-x^2=x^2+2x+1-x^2=2x+1 2x+1 is obviously odd, so only answer choices C and E need to be considered.

2x+1=131 refutes the fact that  2x+1<100  so the answer is C

Video Solution by WhyMath

https://youtu.be/BrEqmDq82rw

~savannahsolver

See Also

2007 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 18
Followed by
Problem 20
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All AJHSME/AMC 8 Problems and Solutions

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