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If John originally had $x$ marbles and Jivanti had $45-x$, and both lost 5 marbles each, then their remaining marbles have product 124. Which quadratic equation in $x$ is obtained?
A$x^2-45x+324=0$
B$x^2-40x+124=0$
C$x^2-45x+200=0$
D$x^2+45x-324=0$
Answer & Solution
Correct answer: A. $x^2-45x+324=0$
After losing 5 marbles each, John has $x-5$ and Jivanti has $40-x$. So $(x-5)(40-x)=124$. Expanding gives $-x^2+45x-200=124$, so $-x^2+45x-324=0$, or equivalently $x^2-45x+324=0$.
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