Question

Evaluate (using formulae) :$\frac{1.25\times 1.25-0.87\times 0.87}{1-0.62}$

• A. $2.24$
• B. $2.12$
• C. $2.56$
• D. $2.74$

Answer 1

The correct option is B $2.12$

$\frac{1.25\times 1.25-0.87\times 0.87}{1-0.62}$

$=\frac{(1.25{)}^2-(0.87{)}^2}{0.38}$

$=\frac{(1.25-0.87)(1.25+0.87)}{0.38}$ [ $\because a^2-b^2=(a-b)(a+b)$]

$=\frac{\left(0.38\right)\left(2.12\right)}{0.38}$

$=2.12$