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 10 of 14.

Harshit Garg said:   10 years ago
Why error% can't be = error/incorrect value?

Suchita said:   10 years ago
Error% = Error/True value.

But we have to calculate error value first.

So, Error = True value-False value.

Here, T.V = 5/3 & F.V = 3/5.

= 5/3-3/5, by solving this we get.

Error = 16/15.

Now, to calculate error%,

Error % = 16/15/5/3*100.

= 16/15*3/5*100 = 16/5*20.

= 64%.

Sam said:   10 years ago
Let the no is 15, then.

3/5*15 = 9.
5/3*15 = 25.

The difference of both is 16.

Then the error percentage is:

Error% = (25-9)/25*100 = 64%.

Subham said:   1 decade ago
= (3/5-5/3)*(5/3)*100.

Srinivas Dama said:   1 decade ago
If the number is x then,

=>x*3/5-x-5/3 = 16/15.

I got 16/15 is the difference of that numbers then how I can go to next step to get the answer can any explain clearly.

Gokul prasanth said:   1 decade ago
Final step is (3x/3x)*100 = 50%.

Manikandan Kuppusamy said:   1 decade ago
Hi, I have one clarification.

Ques: A student multiplied a number by 3 instead of 6. What is the percentage error in the calculation?

As per above step,

We got 6x-3x = 3x, then.

3x*3x*100 = 900%. Is this correct? Please clarify me.

SUNIL said:   1 decade ago
LET Number = 1.

Correct number = 5/3.
Incorrect number = 3/5.

We know that:

%error = (true value- false value)100/(true value).

%error = (5/3-3/5)100/(5/3).

Solve it and you got 64%.

Tips: When ever you got this type of question always choose 1 as no. It make your calculation easier and simplest.

Thanks.

PRIYANKA said:   1 decade ago
True = 5/3.
False = 3/5.

Then false/true*100 = 3/5/5/3*100 = 36% WHICH IS CORRECT %.
TO FIND ERROR PERCENTAGE 100-36 = 64%.

Shiv kumar said:   1 decade ago
Let no. be 100.

100*(3/5) = 60.
100*(5/3) = 166.65.

Error = (true value - false value)/true value.
Error% = error*100.


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