# Aptitude - Percentage - Discussion

Discussion Forum : Percentage - General Questions (Q.No. 4)

4.

What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?

Answer: Option

Explanation:

Clearly, the numbers which have 1 or 9 in the unit's digit, have squares that end in the digit 1. Such numbers from 1 to 70 are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.

Number of such number =14

Required percentage = | 14 | x 100 | % = 20%. | |

70 |

Video Explanation: https://youtu.be/cBamI6iRNIA

Discussion:

96 comments Page 1 of 10.
Durai said:
1 month ago

!All.

Here, They asked 1 or 9, why all answers are included both 1 and 9, if we considered 1 or 9 only the percentage should be 10%.

Correct me, if I'm wrong.

Here, They asked 1 or 9, why all answers are included both 1 and 9, if we considered 1 or 9 only the percentage should be 10%.

Correct me, if I'm wrong.

(1)

Kaviarasan said:
2 months ago

@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.

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.

(1)

Ankush kushwaha said:
3 months ago

1 to 9 = 2 digit (1,9) =2.

11 to 70 = [digit1-tens digit2-units].

At unit one place suppose I have put 1 there that means I have the choice to

put 6 digits at the tens place = 6 * 1 = 6.

similarily for 9 also = 6 *1 = 6.

The reason we are taking 6 digits is because it will exceed the range that is given.

So, total = 14,

14 = x /100 * 70,

x = 20%.

11 to 70 = [digit1-tens digit2-units].

At unit one place suppose I have put 1 there that means I have the choice to

put 6 digits at the tens place = 6 * 1 = 6.

similarily for 9 also = 6 *1 = 6.

The reason we are taking 6 digits is because it will exceed the range that is given.

So, total = 14,

14 = x /100 * 70,

x = 20%.

Manikeshwari said:
4 months ago

@Moses Ug.

We can't consider 12 to 18 because the question says in units place of a number it should either have 1 or 9 not in tens place.

We can't consider 12 to 18 because the question says in units place of a number it should either have 1 or 9 not in tens place.

Gokila said:
4 months ago

Why shouldn't we consider 10, 11, 12, 13, 14, 15, 16, 17, 18 as they have 1 in its unit?

(8)

Aruna said:
1 year ago

Numbers from 1 to 70.

Having 1 or 9 in unit digits,

1 seven times and 9 seven times,

14/70 * 100 = 20.

Having 1 or 9 in unit digits,

1 seven times and 9 seven times,

14/70 * 100 = 20.

(16)

Moses Ug said:
1 year ago

Does 12 up to 18 have a digit 1 or not?

Anyone, please clarify.

Anyone, please clarify.

(15)

Rasheed nasar said:
2 years ago

Very helpful explanation, Thanks. @Tabi.

(3)

Nikhil said:
2 years ago

@Lobsang.

Because, They didn't ask about us anyone's Square.

They just told you to find how many no belongs in 1to70 That last digit should come only 1 and 9. Like 01, 09, 11, 19, 21, 29. 69.

Hope you understood.

Because, They didn't ask about us anyone's Square.

They just told you to find how many no belongs in 1to70 That last digit should come only 1 and 9. Like 01, 09, 11, 19, 21, 29. 69.

Hope you understood.

(19)

LOBSANG said:
2 years ago

Then why don't we consider 7 here because it also ends with 9 as a unit digit 7*7=49?

Anyone clarify it.

Anyone clarify it.

(1)

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