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 1 of 11.
Anand said:
2 weeks ago
To find the percentage of numbers from 1 to 70.
Let's say 1-70 = 100%.
So in there, we want the percentage of 1 and 9 numbers, so we just have to do.
Every 1-70 has 1, and every 1-70 has 9.
So if 1-70 = 100%, 1 is 10% and 9 is 10%, and we sum the percentages, we get 10+10 = 20% answer.
Let's say 1-70 = 100%.
So in there, we want the percentage of 1 and 9 numbers, so we just have to do.
Every 1-70 has 1, and every 1-70 has 9.
So if 1-70 = 100%, 1 is 10% and 9 is 10%, and we sum the percentages, we get 10+10 = 20% answer.
Kannan said:
1 month ago
The number between 1 and 70 should contain 1 or 9 in the unit digits, meaning
The numbers are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.
Total number of 1 or 9 in the unit digits = 14
Then,
They are asking percent so,
14/70 * 100 = 2 * 10 = 20%.
The numbers are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.
Total number of 1 or 9 in the unit digits = 14
Then,
They are asking percent so,
14/70 * 100 = 2 * 10 = 20%.
(2)
Creti said:
6 months 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
(9)
Rohit said:
6 months ago
Why the no. '10' is not included? Please explain to me.
(17)
Tutu said:
10 months ago
How to know if we should take 1 or 70 to make 70 total numbers, like we could have written 13/68 to take a percentage?
Anyone, please explain.
Anyone, please explain.
(9)
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)
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)
Dario said:
2 years ago
The unit's digit (or ones digit) of a number is the digit in the farthest right position. It represents how many ones are in the number.
For example:
In the number 345, the unit's digit is 5.
In the number 82, the unit's digit is 2.
In the number 1090, the unit's digit is 0.
So, when looking for numbers with a specific unit's digit, you're checking the last digit of each number.
For example:
In the number 345, the unit's digit is 5.
In the number 82, the unit's digit is 2.
In the number 1090, the unit's digit is 0.
So, when looking for numbers with a specific unit's digit, you're checking the last digit of each number.
(6)
Anonymous said:
2 years ago
@All.
Here, In 1s digit there are 14 numbers with 1 and 9.
So 70% = 100.
14% = x.
Cross multiply.
70 (x) =14 (100).
X = 1400/70.
X = 20.
Here, In 1s digit there are 14 numbers with 1 and 9.
So 70% = 100.
14% = x.
Cross multiply.
70 (x) =14 (100).
X = 1400/70.
X = 20.
(8)
Bradley S said:
2 years 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%.
(23)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers