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:
105 comments Page 4 of 11.
Faraz said:
8 years ago
It is very simple.
Now there are 14 numbers which start from 1 or 9 It means 14 out of 70.
Now take percentage of 14 out of 70 means multiply by 100 which is equal to 20%.
Now there are 14 numbers which start from 1 or 9 It means 14 out of 70.
Now take percentage of 14 out of 70 means multiply by 100 which is equal to 20%.
Aditya Singh Shishodia said:
5 years ago
@All.
Unit place is the first digit and not the last. As per the place value system it would always begin from left to right. This is simply a wrongly phrased question.
Unit place is the first digit and not the last. As per the place value system it would always begin from left to right. This is simply a wrongly phrased question.
(2)
Durai said:
2 years ago
!All.
Here, They asked 1 or 9, why all answers are included both 1 and 9, if we considered 1 or 9 only the percentage should be 10%.
Correct me, if I'm wrong.
Here, They asked 1 or 9, why all answers are included both 1 and 9, if we considered 1 or 9 only the percentage should be 10%.
Correct me, if I'm wrong.
(15)
Tutu said:
4 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.
(4)
Manikeshwari said:
2 years ago
@Moses Ug.
We can't consider 12 to 18 because the question says in units place of a number it should either have 1 or 9 not in tens place.
We can't consider 12 to 18 because the question says in units place of a number it should either have 1 or 9 not in tens place.
(2)
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.
(7)
Cavendish said:
9 years ago
It has nothing to do with the squares.
Just count the numbers ending with 1 or 9 in between 1 and 70 (inclusively). That's all.
Just count the numbers ending with 1 or 9 in between 1 and 70 (inclusively). That's all.
Abhishek said:
8 years ago
@All.
If we increase the parameter from 70 to 100 then what?
I mean if we count from 1 to 100 than what will be the solution?
If we increase the parameter from 70 to 100 then what?
I mean if we count from 1 to 100 than what will be the solution?
Soujanya said:
10 years ago
What if larger numbers are given?
Eg: 1 to 10000. We cannot count manually all the numbers right, Is there any shortcut?
Eg: 1 to 10000. We cannot count manually all the numbers right, Is there any shortcut?
Renukanth said:
8 years ago
What is the need for squaring here, they just asked to find out how man number are there, with the unit digit (1 and 9)?
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers