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:
107 comments Page 6 of 11.
Yashwitha said:
1 decade ago
Then what about the numbers of 11, 12, 113, 14, 15, 19 even 1 is their, then why it is not considered?
Aruna said:
3 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)
Villan said:
6 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 %.
Ross said:
2 decades ago
I see that number 10 is not included into consideration even though it has 1 in its digit unit, why?
Jim said:
7 years ago
The question is not talking about ending with 1 or 9, but it's talking about numbers having 1 or 9.
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)
Manisha said:
9 years ago
What percentage of numbers from 1 to 90 has a 1 or 9 as one of the digits?
Can anyone solve this?
Can anyone solve this?
Ganesh said:
8 years ago
Simple 1 or 9 in unit digit in 1st 10 no. Is 2,
So 1 to 70 = 2*7 = 14.
% = 14/70*100 = 20% Answer.
So 1 to 70 = 2*7 = 14.
% = 14/70*100 = 20% Answer.
(2)
Priya P. said:
2 decades ago
@chandrakala
Its not end in 1 digit, its end with digit 1
as (1)^2=1
(9)^2=81 ;8(1)
got it..
Its not end in 1 digit, its end with digit 1
as (1)^2=1
(9)^2=81 ;8(1)
got it..
Chandrakala said:
2 decades ago
What about 4? 4 is also squre, so 4, 24, 34, 44, 54, 64 also have squre that end in the digit 1.
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