Question

What number should replace both the asterisks in $(\frac{\ast }{21}\times \frac{\ast }{189})=1$?

• A. $21$
• B. $63$
• C. $147$
• D. $3969$

Answer 1

The correct option is B $63$

Q. What number should replace both

the asterisks in $(\frac{\ast }{21}\times \frac{\ast }{189})=1?$

Sol${}^n\Rightarrow$ we have, $(\frac{\ast }{21}\times \frac{\ast }{189})=1$

So, $(\ast {)}^2=21\times 189$

Let Factories the Number 21 and 189.

So, $21=3\times 7$

$189=3\times 3\times 3\times 7$

So, $(\ast {)}^2=(3\times 7)\times (3\times 3\times 3\times 7)$

$(\ast {)}^2=3^2\times 3^2\times 7^2$

So, $(\ast )=3\times 3\times 7=63$

So, 63 number should replace with

the asterisks sign.