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    (Original post by FarjuIGCSE)
    It was pretty tough. I messed up in the nth term and recurring decimal question. Oh and I wrote rhombus instead of parallelogram :'(
    I got all the other answers though
    Rhombus is not the answer?
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    (Original post by calculus101)
    The exact time I calculated for when the population reaches 10 billion is 3:36 PM 10th August 2042. Wouldn't that still count as in the year 2042? On 1st January 2043, the population would have already exceeded 10 billion.
    Yeah, you might be correct. It depends on how the question was phrased. If it was "What year does it hit 10 billion", then you should be right. I'm starting to feel that you may be right on this one...

    Either way, whether we wrote 2043 or 2042, both our workings are quite correct, so the one who got wrong won't lose much. I think most people who normally get like 66 upwards will get like 58 upwards here, so it should allow for many to get an A. I hope.
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    (Original post by 15demon)
    So someone does agree with my 62. I have like 0 evidence. I mean the right triangle rule only applies to semicircles so.. how did you get 62?
    there were 2 lines from the center till the circumference. each of those lines would be equal because thats the radius. Therefore the triangle is an isoceles triangle. if you multiply 56 by 2 and then subtract it from 180, you get 124. Thats the angle of O. Because any other angle subtended by the same lines as the center is half, the value of C is 62. It's a bit confusing explaining it like this, im sorry if you didnt understand!
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    (Original post by 15demon)
    Rhombus is not the answer?
    no because a rhombus has normal lines of symmetry as well
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    (Original post by 15demon)
    Petroleum Jelly was providing a barrier stopping transpiration. On one leaf add petroleum jelly on the top surface and bottom on the other. Compare the mass change. ?
    thats kinda what i wrote! but apparently you have to use all 4 leaves. one has to have petroleum jelly on both sides and one has to have no petroleum jelly...
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    (Original post by 15demon)
    It was even harder than the Additional math past papers. Oh and i thought you were asking about the other angle question which was from circular measure. For polygon I couldn't come up with a solution but I think the question was an interior angle of a polygon is 173. Calculate number of sides of the polygon. Let's see if someone from TSR can help.
    The answer was 45.
    180(n-2)=172n
    n is the number of sides so the sume of all interior angle=172n
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    (Original post by vasuxx)
    no because a rhombus has normal lines of symmetry as well
    The question only asked for a shape with a rotational symmetry of 2. Or is there something I missed?
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    [QUOTE=15demon;64595241]
    (Original post by small_genius)

    The whole question was 4 marks if I remember correctly .Hope you get your 2 marks
    No it was for 6 marks
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    (Original post by calculus101)
    The exact time I calculated for when the population reaches 10 billion is 3:36 PM 10th August 2042. Wouldn't that still count as in the year 2042? On 1st January 2043, the population would have already exceeded 10 billion.
    I think there is going to be like a 5 year range for answers in the mark scheme
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    (Original post by shaafay)
    Yeah, you might be correct. It depends on how the question was phrased. If it was "What year does it hit 10 billion", then you should be right. I'm starting to feel that you may be right on this one...

    Either way, whether we wrote 2043 or 2042, both our workings are quite correct, so the one who got wrong won't lose much. I think most people who normally get like 66 upwards will get like 58 upwards here, so it should allow for many to get an A. I hope.
    The question was "find which year the population 'reaches' 10 billion". Not the exact words but I think the examiner is looking for 2042.

    I'm aiming for a perfect score in maths so even a single mistake would affect my chances lol.
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    calculus101 how did u calculate the exact time? Quite interesting ?
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    (Original post by rakan_igcse)
    I think there is going to be like a 5 year range for answers in the mark scheme
    It was for 2 marks though, 5 years range would be a bit over the limit. 2043 can still be considered however.
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    (Original post by small_genius)
    calculus101 how did u calculate the exact time? Quite interesting ?
    Using logarithms (out of syllabus but the only way to obtain exact exponents), one would get 28.6132751396 years. That's 28 years and 223.8454259708 days. Considering the fact that the year 2042 is NOT a leap year(thus February=28days), you can subtract the months one by one until you obtain a value below 30 days. Which is 11.8454259708 days AFTER the end of July. So far, the date is 2042 August 11. (I used 28.61 years so I was off by a day). Then you can convert 0.8454259708 into hours. Which is 20 hours and 17.4 minutes. Thus, the exact time is 8:17 PM 11th August 2042.

    Forgive my previous approximation(3:36 PM 10th August 2042), it was too inaccurate.
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    You are funtastic I just did compound interest formula and got 2043 lol😁
    (Original post by calculus101)
    Using logarithms (out of syllabus but the only way to obtain exact exponents), one would get 28.6132751396 years. That's 28 years and 223.8454259708 days. Considering the fact that the year 2042 is NOT a leap year(thus February=28days), you can subtract the months one by one until you obtain a value below 30 days. Which is 11.8454259708 days AFTER the end of July. So far, the date is 2042 August 11. (I used 28.61 years so I was off by a day). Then you can convert 0.8454259708 into hours. Which is 20 hours and 17.4 minutes. Thus, the exact time is 8:17 PM 11th August 2042.

    Forgive my previous approximation(3:36 PM 10th August 2042), it was too inaccurate.
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    (Original post by small_genius)
    You are funtastic I just did compound interest formula and got 2043 lol😁
    Well for a guy who knows up to multivariable calculus and differential equations, IGCSE mathematics is child's play.
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    (Original post by small_genius)
    You are funtastic I just did compound interest formula and got 2043 lol😁

    This might sound a little crazy but what if we round the month AUGUST to the nearest year since August is the 8 th moth we could round it to 2043
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    I too got the answer as 2043. Anyhow, has anyone come across the unofficial mark scheme yet?
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    (Original post by 15demon)
    Do you remember what the mode value was from the question about finding 4 numbers given mean, median and mode?
    68,76,78 and 78
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    (Original post by emilyy_elizabeth)
    Well I think that's one of the only questions I kind of understood. I think I got something like
    a) a+b-c
    b) half iof a so 1/2(a+b-c0
    c) 1/2a- 1/2c+ 5/6b or something similar
    Yess way to go!
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    My teacher who marks igcse maths said the answer is 2042
 
 
 
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