Question

The distance travelled by a superjet is $(x-6{)}^2$ m in time $x^2-6^2$ secs, then the speed of the superjet is m/sec.

• A. $\frac{6}{x+6}$
• B. $\frac{x-6}{x+6}$
• C. $\frac{x+6}{x-6}$

Answer 1

The correct option is B $\frac{x-6}{x+6}$

Given,
Distance = $(x-6{)}^2$ m
TIme = $x^2-6^2$ secs

Then, the speed of the superjet $=\frac{Distance}{Time}$

Now, using the identity,
$x^2-y^2=(x+y)\times (x-y)$
$x^2-6^2=(x+6)\times (x-6)$

Speed of the superjet $=\frac{(x-6{)}^2}{x^2-6^2}$ m/sec
$=\frac{(x-6{)}^2}{(x+6)\times (x-6)}$ m/sec
$=\frac{x-6}{x+6}$ m/sec