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#1 2018-08-05 15:27:48
- Zeeshan 01
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- Registered: 2016-07-22
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Increase and decrease in quantity
If 450 is first increased by 10% and then decreased by 15% , Then the resulting number is?
Malik
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#2 2018-08-05 17:13:31
- Jai Ganesh
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- Registered: 2005-06-28
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Re: Increase and decrease in quantity
Hi Zeeshan 01,
450 is increased by 10% : Resulting in 450 + 45 = 495.
Later, it is decreased by 15%.
That is, 495 - (15/100) x 495 = 495 - 74.25 = 420.75.
If the problem is intended : 450 is first increased by 10% and decreased by 15%, the net effect being decrease in 5%;
In this case, the value would be 450 - 450 x 5/100 = 450 - 22.5 = 427.50.
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
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#3 2018-08-05 20:24:19
- Zeeshan 01
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- Registered: 2016-07-22
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Re: Increase and decrease in quantity
Ok! The difference between these two
Malik
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#4 2018-08-05 23:52:30
- Jai Ganesh
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- Registered: 2005-06-28
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Re: Increase and decrease in quantity
Hi,
The difference between the two : 427.50 - 420.75 = 6.75.
This can be calculated with any hand held calculator.
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
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#5 2018-08-06 03:20:32
- Zeeshan 01
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Re: Increase and decrease in quantity
Not this difference , Means the difference between methods and when to use
Malik
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#6 2018-08-06 13:49:41
- Jai Ganesh
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- Registered: 2005-06-28
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Re: Increase and decrease in quantity
Hi,
The first method is technically correct.
It is always advisable to use this method.
The second method may give more of less the same value.
This is for the beginners.
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
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#7 Yesterday 01:33:46
- mycalsuite
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- Registered: 2025-09-10
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Re: Increase and decrease in quantity
If 450 is first increased by 10% and then decreased by 15% , Then the resulting number is?
Answer: 420.75
mycalsuite
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#8 Yesterday 13:19:28
- Phrzby Phil
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- From: Richmond, VA
- Registered: 2022-03-29
- Posts: 65
Re: Increase and decrease in quantity
The first method is technically correct.
It is always advisable to use this method.
The second method may give more of less the same value.
This is for the beginners.
I'm not in agreement with "technically correct." The first method IS correct.
Any method that gives "more or less the same value" is incorrect. In this case, what does it mean to change 450 twice, when after the first change you no longer have 450?
Why would you want beginners to use an incorrect method?
Last edited by Phrzby Phil (Yesterday 13:21:26)
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#9 Yesterday 15:40:10
- Jai Ganesh
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- Registered: 2005-06-28
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Re: Increase and decrease in quantity
Jai Ganesh wrote:The first method is technically correct.
It is always advisable to use this method.
The second method may give more of less the same value.
This is for the beginners.I'm not in agreement with "technically correct." The first method IS correct.
Any method that gives "more or less the same value" is incorrect. In this case, what does it mean to change 450 twice, when after the first change you no longer have 450?
Why would you want beginners to use an incorrect method?
Any Mathematics problem and solution have Levels of Difficulty/Simplicity.
I always choose the best and most accurate method.
Technically Correct: Something which is accurate according to a strict interpretation of rules, facts, or a specific system, even if it's not the most practical or common way of thinking about it.
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
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