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:
105 comments Page 11 of 11.
Sanjana said:
7 years ago
@Shubham.
12^2 = 144 here, the last digit in 144 is four not "1" that's y 12 is not being taken.
Therefore, if the number with the last digit 1 and it's square the last digit is 1 is not being taken!
And it's the same with the other number like 13, 17.. and all!!
Got it?
12^2 = 144 here, the last digit in 144 is four not "1" that's y 12 is not being taken.
Therefore, if the number with the last digit 1 and it's square the last digit is 1 is not being taken!
And it's the same with the other number like 13, 17.. and all!!
Got it?
Jim said:
6 years ago
The question is not talking about ending with 1 or 9, but it's talking about numbers having 1 or 9.
Arushi said:
5 years ago
@Jim.
The unit digit is the ending digit.
The unit digit is the ending digit.
Villan said:
5 years ago
The simplest method is by counting the unit places as 3 and 7.
So, there are 14 nos.
14/70*100=20 %.
So, there are 14 nos.
14/70*100=20 %.
Creti said:
2 weeks ago
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
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
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers