Question

Evaluate $30.5\times 29.5$ without actual multiplication.

• A. $890.25$
• B. $999.75$
• C. $889.25$
• D. $899.75$

Answer 1

The correct option is D $899.75$

We know $30.5\times 29.5=(30+0.5)(30-0.5)$

We know that $(x+y)(x-y)=x^2-y^2$

Here $x=30$ and $y=0.5$

Therefore, the value of $(30+0.5)(30-0.5)$ is

$=(30{)}^2-(0.5{)}^2$

$=900-0.25$

$=899.75$