Pappu multiplied a number by 2/5 instead of 5/2, What is the percentage error in the calculation ?

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18 Jun 2020 Percentage Error

Pappu multiplied a number by 2/5 instead of 5/2, What is the percentage error in the calculation ?

OPtion

1) 18%
2) 84%
3) 25%
4) 14%
5) 60%
6) 33%
7) 81%
8) 75%
9) 90%
10) None of these

Solution

Let the number be x.

Then, ideally he should have multiplied by x by 5/2. Hence Correct result was x * (5/2)= 5x/2.



By mistake he multiplied x by 2/5 . Hence the result with error = 2x/5

Then, error = (5x/2 - 2x/5) = 21x/10

Error % = (error/True value) * 100 = [(21/10) * x / (5/2) * x] * 100 = 84 %

Correct Option: 2 Best Solution (1)

SAYAN CHATTERJEE   3 years AGO

(5x/2-2x/5)/(5x/2)*100%
= 84%.
Option 2.

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