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 8 of 11.
Ajinkya said:
9 years ago
11, 19 is a prime number. So why they are included in squares?
Panda said:
8 years ago
Why 1s of 12, 13,14...,18 is not calculated? Please explain.
Vamshi sai said:
8 years ago
I didn't get question properly can anyone help me to get it.
RAVI TEJA ADARI said:
1 decade ago
Why should take ends with '1'?
Why not take other numbers?
Why not take other numbers?
Laxman said:
7 years ago
In question there should be 1 & 9 instead of 1 or 9.
(1)
Preethy said:
6 years ago
I am not understanding the answer, please explain it.
Shubham matekar said:
6 years ago
Why 12, 13... 17 has not considered? Please tell me.
Emma said:
10 years ago
Thanks guys I've got the first question so clearly.
Abhishek said:
7 years ago
If we count without unit digit. What is the answer?
Udit said:
8 years ago
Why 7 not included? It ends with 9 after squaring.
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