Once you attempt the question then PrepInsta explanation will be displayed.

Explanation:

For any this type of question, remember

Product of two numbers = Product of their HCF and LCM

So Other number = (693*11)/99 = 77

**Easy trick is**

We all know

Product of two numbers = Product of their HCF and LCM

So, 693*11 = 99*X

now look closely at the last digits on LHS, which are 3 and 1. Thus, if you definitely multiply 693*11 the units digit of the result will be 3 only.

Out of the which, options should 99 which has units digit as 9 be multiplied by so you also get units digit as 3. The only option is 7

As 9*7 = 63 which has units digit as 3.

**Now, this is how smart people will solve it as it doesn't need any pen or paper. You can solve this in mind within 5 seconds.**