Reverse Percentages
Maths and statistics discussion, revision, exam and homework help.
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Reverse Percentages
The question is:
In a class there are 9 people absent. This is 20% of the class
How many are there in the class when no-one is off ill?
so to work out i did: 1.8*9=16.2
but 10% of the question is 4.5 and 4.5*10= 45 (Half of 20 is 10 and half of 9 is 4.5)
so i recon 45 is the answer but how do I work it out the first way? -
Re: Reverse PercentagesYes, 45, is the correct answer.(Original post by S_Kid)
The question is:
In a class there are 9 people absent. This is 20% of the class
How many are there in the class when no-one is off ill?
so to work out i did: 1.8*9=16.2
but 10% of the question is 4.5 and 4.5*10= 45 (Half of 20 is 10 and half of 9 is 4.5)
so i recon 45 is the answer but how do I work it out the first way?
Lets say that the total number of students in the class are
So we can form the equation as below,
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Re: Reverse PercentagesThere is no reason to do this. I was just telling you that this was probably the way in which the OP worked out 1.8, however, it looks wrong to do this.(Original post by TenOfThem)
Maybe but ... why would they then do 1.8x9? -
Re: Reverse PercentagesYeah .. the method was clearly wrong I was just trying to figure out what their thinking was(Original post by raheem94)
There is no reason to do this. I was just telling you that this was probably the way in which the OP worked out 1.8, however, it looks wrong to do this. -
Re: Reverse PercentagesThe OP is asking for help, and you aren't being of any help by giving such harsh opinions.(Original post by AGrumpyMole)
Seriously, if you can't do this, go to primary school.
There is no shame on asking a simple question, he is at least trying to learn it. -
Re: Reverse PercentagesIt is only easy if you know the answer.(Original post by AGrumpyMole)
Seriously, if you can't do this, go to primary school.