Aptitude - Percentage - Discussion
Discussion Forum : Percentage - General Questions (Q.No. 9)
9.
| A student multiplied a number by | 3 | instead of | 5 | . |
| 5 | 3 |
What is the percentage error in the calculation?
Answer: Option
Explanation:
Let the number be x.
| Then, error = | 5 | x - | 3 | x = | 16 | x. |
| 3 | 5 | 15 |
| Error% = |  |
16x | x | 3 | x 100 |  % = 64%. |
| 15 | 5x |
Discussion:
135 comments Page 10 of 14.
Maggi said:
8 years ago
A Person has multiplied a number by 3/5 instead of 5/3.
For simplicity consider the number as 15.
15*(3/5)=9 and 15*(5/3)=25.
the person should have got ans as 25 but because of his mistake, he got 9.
Error is 25-9=16 convert to percentage
if 25 is 100%
16--->?
(16*100)/25= 64%.
Here I considered the number to be 15 since it easily divides by the denominator.
For simplicity consider the number as 15.
15*(3/5)=9 and 15*(5/3)=25.
the person should have got ans as 25 but because of his mistake, he got 9.
Error is 25-9=16 convert to percentage
if 25 is 100%
16--->?
(16*100)/25= 64%.
Here I considered the number to be 15 since it easily divides by the denominator.
Jagadeesh said:
8 years ago
@Sasi.
How can you write (3/5) (3/5) (5/3) can you explain?
How can you write (3/5) (3/5) (5/3) can you explain?
Mohan said:
8 years ago
Thanks @Sudharshan.
Madhu said:
8 years ago
Why should we divide by true value at last?
Aditya said:
8 years ago
Easier method. Think of a number divisible by both 5 and 3. Let's say x=15.
True Value = (5/3)*15 = 25.
Wrong Value = (3/5)*15 = 16.
Now calculate the error : 9/25 * 100.
64% is correct.
True Value = (5/3)*15 = 25.
Wrong Value = (3/5)*15 = 16.
Now calculate the error : 9/25 * 100.
64% is correct.
Mahima said:
8 years ago
Thank you all for the solution.
Rajendra Samir said:
8 years ago
Thanks All.
Pinky said:
8 years ago
How we get 64%?
Mohd Zeeshan said:
8 years ago
Thanks @Hari.
Raghava said:
8 years ago
I can't this. So, please explain me in a simple way.
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