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 3 of 11.
Shahira said:
1 year ago
Numbers from 1 to 70.
1 unit digit -> 1,11,21,31,41,51,61 -> 7 numbers.
9 unit digit -> 9,19,29,39,49,59,69 -> 7 numbers.
So, the total 1 and 9 unit digits is 14 numbers.
Now percentage;
14/70 * 100 = 20%.
1 unit digit -> 1,11,21,31,41,51,61 -> 7 numbers.
9 unit digit -> 9,19,29,39,49,59,69 -> 7 numbers.
So, the total 1 and 9 unit digits is 14 numbers.
Now percentage;
14/70 * 100 = 20%.
(32)
Jeetendra Kushwaha said:
1 decade ago
Please read the question carefully.
It says about that number which put in place of a unit and which must be 1 or 9.
So only these number are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.
So total 14 numbers.
It says about that number which put in place of a unit and which must be 1 or 9.
So only these number are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.
So total 14 numbers.
Basha said:
6 years ago
In every ten numbers, we have only two numbers that end with digits 1 or 9.
So b/w 1 to 70 we 14. (7*2 = 14).
Here 7 represents no of tens and 2 represents no of numbers that end with digit 1 or 9.
So, 14/70 * 100 = 20.
So b/w 1 to 70 we 14. (7*2 = 14).
Here 7 represents no of tens and 2 represents no of numbers that end with digit 1 or 9.
So, 14/70 * 100 = 20.
(2)
Syed Rasheed said:
1 year ago
1-10 = 2 available 1,9.
11-20 = 2 available 11,19.
21-30 = 2 available 21,29.
31-40 = 2 available 31,39.
41-50 = 2 available 41,49.
51-60 = 2 available 51,59.
61-70 = 2 available 61,69.
Q1/q2 ×100.
= 14/70 ×100
= 20.
11-20 = 2 available 11,19.
21-30 = 2 available 21,29.
31-40 = 2 available 31,39.
41-50 = 2 available 41,49.
51-60 = 2 available 51,59.
61-70 = 2 available 61,69.
Q1/q2 ×100.
= 14/70 ×100
= 20.
(19)
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.
(20)
PANKAJ said:
2 decades ago
@ ROSS
The no 10 after squaring it does not end with 1.......
if u square to 1,11,19,21 it ends with 1
Squaring 10 = 10 x 10 = 100 it ends with 0
Squaring 11 = 11 x 11 = 121 it ends with 1
I think u got it.
The no 10 after squaring it does not end with 1.......
if u square to 1,11,19,21 it ends with 1
Squaring 10 = 10 x 10 = 100 it ends with 0
Squaring 11 = 11 x 11 = 121 it ends with 1
I think u got it.
Zaman said:
1 decade ago
We should first understand the question ?
The question asks the numbers with 1 or 9 in the unit digit that is in the last digit or ending with 1 or 9.
12, 13, 14 have 2, 3 and 4 in the unit digit respectively.
The question asks the numbers with 1 or 9 in the unit digit that is in the last digit or ending with 1 or 9.
12, 13, 14 have 2, 3 and 4 in the unit digit respectively.
Puja said:
8 years ago
The Units digit is the digit in the one's column.
Ex-4567, 876, 53.
Unit digit 7,6, 3.
Now come to solution;
1to 70 unit digits are 1,9,11,19,21,29,31,39,41,49,51,59,61,69 =14.
So percentage =14/70*100= 20%.
Ex-4567, 876, 53.
Unit digit 7,6, 3.
Now come to solution;
1to 70 unit digits are 1,9,11,19,21,29,31,39,41,49,51,59,61,69 =14.
So percentage =14/70*100= 20%.
Daniel said:
1 decade ago
The question doesn't specify that the digits 1 or 9 must be the last digits, so clearly all the number in the teens, would qualitfy as nubers between 1 and 70 that have the digit 1 OR 9.
Uttam said:
1 decade ago
Inside the 10 there are 2 digits which ends with 1 and 9.
Number 70 consists 7 tens.
So total no of digits that end with 1 and 9 in 70 are,
7*2=14.
So percentage= (14/70) *100=20.
Number 70 consists 7 tens.
So total no of digits that end with 1 and 9 in 70 are,
7*2=14.
So percentage= (14/70) *100=20.
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