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:
101 comments Page 1 of 11.
Nikhil said:
3 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)
Aruna said:
2 years 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.
(17)
Moses Ug said:
2 years ago
Does 12 up to 18 have a digit 1 or not?
Anyone, please clarify.
Anyone, please clarify.
(15)
Gokila said:
1 year ago
Why shouldn't we consider 10, 11, 12, 13, 14, 15, 16, 17, 18 as they have 1 in its unit?
(15)
Bradley S said:
9 months ago
@All.
Here, they have incorrectly missed the number range from 11-20, which includes 10 numbers (not 2). The ranges from 1-70, which include a 1 or 9. 11, 12, 13, 14, 15, 16, 17, 18, 19 = 10. All from 1 - 70 have 2. Therefore the total sum = 22/70 which equates to 31%.
Here, they have incorrectly missed the number range from 11-20, which includes 10 numbers (not 2). The ranges from 1-70, which include a 1 or 9. 11, 12, 13, 14, 15, 16, 17, 18, 19 = 10. All from 1 - 70 have 2. Therefore the total sum = 22/70 which equates to 31%.
(12)
Durai said:
11 months 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.
(10)
Basharat Mir said:
9 months ago
To find the percentage of numbers from 1 to 70 that have 1 or 9 in the unit's digit, we first identify all such numbers.
Numbers with 1 in the unit's digit:
1, 11, 21, 31, 41, 51, 61
Numbers with 9 in the unit's digit:
9, 19, 29, 39, 49, 59, 69
Each set has 7 numbers.
Combining both sets, we have:
1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69,
In total, there are 14 numbers from 1 to 70 with either 1 or 9 in the unit's digit.
Percentage = ( Number of desired numbers)/Total numbers × 100.
Percentage = (14/70)× 100 = 20%.
Therefore, 20% of the numbers from 1 to 70 have either 1 or 9 in the unit's digit.
Numbers with 1 in the unit's digit:
1, 11, 21, 31, 41, 51, 61
Numbers with 9 in the unit's digit:
9, 19, 29, 39, 49, 59, 69
Each set has 7 numbers.
Combining both sets, we have:
1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69,
In total, there are 14 numbers from 1 to 70 with either 1 or 9 in the unit's digit.
Percentage = ( Number of desired numbers)/Total numbers × 100.
Percentage = (14/70)× 100 = 20%.
Therefore, 20% of the numbers from 1 to 70 have either 1 or 9 in the unit's digit.
(8)
Manjunath Halageri said:
3 years ago
I think the total numbers are 15 because here, the number 10 is missed.
10 also have the number 1.
10 also have the number 1.
(5)
Rasheed nasar said:
3 years ago
Very helpful explanation, Thanks. @Tabi.
(3)
Kaviarasan said:
12 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.
(3)
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