How to do this question ?

Dear Shreya,

There are quick tricks to solve this question, but I would explain here using fundamentals of rounding-off.

Purpose of rounding off a number to x is to be able to write the number in terms of x without using decimal.

For rounding a number to nearest x (which is lakh in this case), we need to think of a number line with unit x.

For this case number line would look like this,

----------|----------|----------|----------|----------|
         178        179        180        181
(178, 179 ... are in lakhs)

Now lets find the place for 179.97182 lakh on this line (remember we want to get rid of decimals).

----------|----------|----------|----------|----------|
         178        179       * 180       181

Place for 17.997182 lakh is approximately shown as * on the line.

Here you could see that this number is closer to 180 lakh, so rounded-off number will be 180 lakhs (18000000).

regards,

ExamHelp