Aptitude - Percentage - Discussion

I think the total numbers are 15 because here, the number 10 is missed.

10 also have the number 1.

The unit's digit (or ones digit) of a number is the digit in the farthest right position. It represents how many ones are in the number.

For example:
In the number 345, the unit's digit is 5.
In the number 82, the unit's digit is 2.
In the number 1090, the unit's digit is 0.
So, when looking for numbers with a specific unit's digit, you're checking the last digit of each number.

How to know if we should take 1 or 70 to make 70 total numbers, like we could have written 13/68 to take a percentage?

Anyone, please explain.

Why the no. '10' is not included? Please explain to me.

Very helpful explanation, Thanks. @Tabi.

@All.

Here is my explanation for the answer.

Let's take initial values as 100%, which means initially the fruit seller had some apples, so I take that as 100%.

Now, if he sells 40% of his apples, he has 60% of the apples remaining.

So, in the question, they have already stated that the seller has 420 apples after selling 40%.

Thus, we have:
60% = 420.
100% = x.

To solve this expression:
x = (420×100)60x = 60(420×100)​.
x = 700x = 700.

Therefore, the answer is 700.

It's Very Easy:

Here, the numbers from 1 to 70 have 1 or 9.
In the units digit?

So, we have 1 to 70.

1 or 9 - here 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.
Here, 14 are there;
14/70 × 100.
14/7 × 10.
(140/7) = 20.

Here, the answer is 20

In every ten numbers, we have only two numbers that end with digits 1 or 9.
So b/w 1 to 70 we 14. (7*2 = 14).
Here 7 represents no of tens and 2 represents no of numbers that end with digit 1 or 9.
So, 14/70 * 100 = 20.

What is the unit's digit? Please explain me.

Why don't we consider the 12, 13, 18 because it has 1 as a unit digit?