Aptitude - Percentage - Discussion

Then what about the numbers of 11, 12, 113, 14, 15, 19 even 1 is their, then why it is not considered?

Thanks guys I've got the first question so clearly.

7x7= 49.

4(9) why don't we count 7 then?

What about 12 13 14, 15, 16, 17, 18?

Hello friends here they asked just between numbers from 1 to 70 so we followed this procedure. It is not easy to find if they asked for larger numbers like 1 to 10000 like this. In this case can't keep go on counting so please tell a new shortcut method.

Hello friends! in the question, not mentioned that the word "square".

Why don't you take 12, 13, 14...?

@Nicky.

I think you know what is unit's digit?

So from the given question, we have to count the numbers between 1-70.

Which have 1 and 9 in their unit's digit. They are:

1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69 these are numbers we are looking for. And these are having only 1 and 9 in their unit's digit.

So the count of the above numbers is 14.

Then we have calculate the percentage of 14 in 70.

So we assume the percentage is x.

Hence (x/100)*70 = 14.

70x/100 = 14.
70x = 1400.
x = 1400/70 = 20.
x = 20%.

In question he said 1 or 9 in the units digit there are 4 numbers between 1 to 10 whose unit digit ends between 1 and 9 they are 1, 3, 7, 9 so tell me that what is the solution?

Hai raju I can solve your problem:

Let us consider the number be = x.

25%of that number = 25*(x/100) = x/4(let us say as y).
And also given that 18% of 650 = 18*(650/100) = 117.

(Once read 1st line of question).

It means that y is less than 117 by 19 so; 117-y = 19.
117-(x/4) = 19.
so x = 392.