ABC26GN0986 · Simplification

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

If $(a-b)=4$ and $a b=2$, then $\left(a^{2}+b^{2}\right)=$ ?
(a)18
(b)20
(c)25
(d)None of these
Answer
Answer (as printed): B
Explanation
$(a-b)=4 \Rightarrow(a-b)^{2}=4^{2}=16 \Rightarrow a^{2}+b^{2}-2 a b=16$ $$\begin{aligned} \Rightarrow a^{2}+b^{2} & =16+2 a b=16+2 \times 2 \\ & =16+4=20 . \end{aligned}$$

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

Open in whiteboard · Browse this chapter in the app