ABC26GN1203 · Simplification

Subject: General Aptitude · Chapter: Simplification · Exam: 2003 · Marks: · Difficulty:

If $a-b=3$ and $a^{2}+b^{2}=29$, find the value of $a b$.
(a)10
(b)12
(c)15
(d)18
Answer
Answer (as printed): A
Explanation
$$2 a b=\left(a^{2}+b^{2}\right)-(a-b)^{2}=29-9=20 \Rightarrow a b=10 .$$

Explanation as extracted from the printed page; notation may be imperfect.

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