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?

34%
44%
54%
64%
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:
134 comments Page 9 of 14.

MaDX said:   9 years ago
@Raj, We have to find error %.
And like S.P and C.P, the percentage are calculated from the original value.

1.First we have to find the error:

Error = Original value - Wrong value.
= (5/3 x) - (3/5 x).
= 16/15x.

2.Then percentage for error in original.
error% = error/original * 100;
= (16/15 x)/(5/3 x) * 100.
= 64%.

So 64%.

Rakesh said:   9 years ago
Great answer @Srihari.

Ganesh said:   9 years ago
@Sudershan. Thanks for your solution.

Sharmila said:   9 years ago
I understand multiplication errors but what if someone substracted a number instead of adding?Can we still calculate %error? If can't why?

Please explain someone.

Sudhan said:   9 years ago
@Srihari.

Your method is awesome, Thank you.

Srilekha said:   8 years ago
If we get error as a negative number them what we have to do?

Madhu said:   8 years ago
Error%={(true value-false value)/true value}*100.
={(5/3-3/5)/5/3}*100,
={16/25}*100,
=64%.

Pavithradevi M said:   8 years ago
Gain % = error ÷ false value * 100 if we put this problem by this formula we can't get 64%. Then how to get it?

Ishak Khan said:   8 years ago
Can it be negative?

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.


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