Question

The value of 249² – 248² is
(a) 1
(b) 477
(c) 487
(d) 497

Answer 1

$$\begin{gathered} {\left(249\right)}^2-{\left(248\right)}^2 \\ =\left(249+248\right)\left(249-248\right)\left(\mathrm{Using}\mathrm{the}\mathrm{identity}:a^2-b^2=\left(a+b\right)\left(a-b\right)\right) \\ =\left(497\right)\left(1\right) \\ =497 \\ \mathrm{Hence},\mathrm{the}\mathrm{correct}\mathrm{option}\mathrm{is}\left(\mathrm{d}\right). \end{gathered}$$