Which is the correct method for increasing a number by a Percentage?

8 Comments / Mathematics / By Melvin Vincent

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Please share your knowledge about this discussion point as comment of this post in this website itself. We will get two different values from the two methods shown in the picture. Which is correct?. If one method is correct, what is wrong in other method?. Thanks in advance.

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Tri Hoang

4 years ago

Increase 50 by 15% mean 50 plus 15% of 50. So the correct one is 50 + 50*15% = 50(1+15%)

Melvin Vincent

Author

Reply to Tri Hoang

4 years ago

Thank You Tri Hoang for participating in this discussion. And you are correct. Thank you once again.
Founder
Know Industrial Engineering

Melvin Vincent

Author

4 years ago

I will explain for what purpose we are using first formula (50/0.85). Its used for calculating the number whose 85% is 50.

Founder
Know Industrial Engineering

Melvin Vincent

Author

4 years ago

Any one knows the application of the formula [a number/a percentage] in industrial engineering?

Sneh Mulani

Reply to Melvin Vincent

4 years ago

Can you please share your experience with us

Melvin Vincent

Author

Reply to Sneh Mulani

4 years ago

Ok I will share.

The formula [a number/a percentage] can be used for calculating the cycle time of an operation at a particular efficiency.

Example : Suppose the cycle time of a operation is 9 minutes at 100% efficiency and we want to calculate the cycle time at 85% efficiency, it can be calculated by 9/0.85, which is 10.58 minutes.

Thank you,
Melvin Vincent
Founder
Know Industrial Engineering

Melvin Vincent

Author

Reply to Melvin Vincent

4 years ago

I will also explain how we got the formula [a number/a percentage] for calculating the cycle time of an operation at a percentage of efficiency.
I will take the above example for explaining this.
@ 100% efficiency the cycle time of an operation is 9 minutes and the work done to be done in one cycle is W.
Now we got an equation 1
W/9=w1
Here w1 is the work done in a unit time at 100% efficiency.
Like this we will get another equation, equation 2
W/x=w2
Here w2 is the work done in a unit time at 85%efficiency
And x is what we needed, cycle time at 85% efficiency.
Since x is cycle time at 85% efficiency, w2=w1*85%
The third equation.
By solving these three equations we get the result
x=9/85%