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:
102 comments Page 11 of 11.
Syed Rasheed said:
7 months 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.
(13)
Shahira said:
3 months 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%.
(9)
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