Percentages

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Percentages

by shaifali84 » Tue Oct 09, 2018 3:10 am
Price of coal is up by 40%. Mr Amir must reduce the consumption by what percentage to remain at par. (source: Simplified Mathematics)

a) 60
b) 66
c) 2084
d) 60
e) 71.4

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Answer

by coolhabhi » Tue Oct 09, 2018 5:36 am
shaifali84 wrote:Price of coal is up by 40%. Mr Amir must reduce the consumption by what percentage to remain at par. (source: Simplified Mathematics)

a) 60
b) 66
c) 2084
d) 60
e) 71.4
Lets think initially the Price of Coal is 100$/Ton and Mr Amir uses 10Tonnes. Hence total value (initially) is 100x10 = 1000$

Now the Price of Coal is 140$/Ton and to remain at par, lets assume the consumption is "c".
Hence,

1000 = 140xc
100/14 = c
c=71.4.

Hence the is the reduced consumption percentage will be (100-71.4) = 38.6%. But I don't see this in the options.

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by shaifali84 » Tue Oct 09, 2018 6:24 am
yes, your answer is not the option in this question. The answer is 71.4, don't know how?

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by prabsahi » Wed Oct 10, 2018 5:58 am
shaifali84 wrote:Price of coal is up by 40%. Mr Amir must reduce the consumption by what percentage to remain at par. (source: Simplified Mathematics)

a) 60
b) 66
c) 2084
d) 60
e) 71.4

The options dont seem to make sense.

Let price be 100 then increased price is 140.By what percentage do we need to reduce this 140 so that it is equal to 100

40/140*100= 27%
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reply

by prabsahi » Wed Oct 10, 2018 6:06 am
prabsahi wrote:
shaifali84 wrote:Price of coal is up by 40%. Mr Amir must reduce the consumption by what percentage to remain at par. (source: Simplified Mathematics)

a) 60
b) 66
c) 2084
d) 60
e) 71.4

The options dont seem to make sense.
Lets assume we consume of 10 kg of $100 product.Now let the consumption be X after price is reduced to 140
100*10=140*x
X=1000/140=100/14=50/7=7.14

Now initial consumption was 10kg and new consumption is 7.14

So he should reduce by (10-7.14)/10 =apprx 30%

[color=]I think the last option is wrong.It seems the question maker has assumed
"Mr Amir must reduce the consumption by what percentage" as 7.14 but it should be[/color] 30%
If you want to fly,you have to give up the things that weighs you down!

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