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:
103 comments Page 2 of 11.
Manikeshwari said:
2 years 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.
(2)
Gokila said:
2 years ago
Why shouldn't we consider 10, 11, 12, 13, 14, 15, 16, 17, 18 as they have 1 in its unit?
(16)
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:
3 years ago
Does 12 up to 18 have a digit 1 or not?
Anyone, please clarify.
Anyone, please clarify.
(15)
Rasheed nasar said:
3 years ago
Very helpful explanation, Thanks. @Tabi.
(3)
Nikhil said:
4 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:
4 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)
Manjunath Halageri said:
4 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)
Shivam Tripathi said:
5 years ago
There are 10 digits from 0 to 9 total( 10 nos) out of which 1 and 9 are asked in question (2 digits) so in question at units place Bo's are not repeating.
Hence 2 digits out of 10 digits Make it 20%(2/10=20%).
Am I right?
Hence 2 digits out of 10 digits Make it 20%(2/10=20%).
Am I right?
(2)
Aditya Singh Shishodia said:
5 years ago
@All.
Unit place is the first digit and not the last. As per the place value system it would always begin from left to right. This is simply a wrongly phrased question.
Unit place is the first digit and not the last. As per the place value system it would always begin from left to right. This is simply a wrongly phrased question.
(2)
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