Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    Offline

    0
    ReputationRep:
    Isn't the answer to the question regarding the year when population equals 10 billion 2042? Using the compound interest formula, it'll take around 29 years or on January the 1st of 2043 for the population to reach OVER 10 billion (you get a decimal). Wouldn't that mean that the population REACHED the 10 billion mark the year prior? 2042?
    • Thread Starter
    Offline

    3
    ReputationRep:
    i got 29 but i forgot to add since the time finished but i reckon id get a mark for that
    Offline

    0
    ReputationRep:
    This is how I did it:

    7.23(1 + 0.0114)^x = 10
    With x being the number of years.

    Through trial and error: when x = 28, the population is 9.930723215 billion. 28 + 2014 (January 1st) = 2042 January 1st.

    When x = 29, the population is 10.04393346 billion. 29 + 2014 (January 1st) = 2043 January 1st.

    This means that on the 1st of January 2043, the population was OVER 10 billion. That means the population hit 10 billion sometime between the 28th and 29th year after 2014. So it's sometime in 2042.

    X in the above equation is revealed to be 28.6133 (algebraically without trial and error), so it couldn't have been in 2043 when the population hit 10 billion because it's gone over by then. In fact if it's 28.6133 years after 2014, then it would be sometime in July of 2042, not 2043.
    • Thread Starter
    Offline

    3
    ReputationRep:
    We should all move on the gt is bound to be under 50 MBamirny since a 2012 paper which was easier had a gt of 48 for an A what would this one have
    Offline

    16
    ReputationRep:
    I wanna see this paper. Harder than the '15 one? :ninja:
    Offline

    7
    ReputationRep:
    Honestly Maths was horrible I have done 30 past papers scoring A and above, no joke and this one was the hardest i've come across.
    Offline

    2
    ReputationRep:
    IT was very difficult :// I got the mean medium mode question, it was 78,78,76,and 68
    Offline

    2
    ReputationRep:
    (Original post by Imperion)
    I wanna see this paper. Harder than the '15 one? :ninja:
    yeah, much harder. I solved that one with ease this was a struggle
    Offline

    2
    ReputationRep:
    (Original post by ladyanonimous)
    If i remember, the answer to that is 45
    I got that too! you do 180 x (n-2) = 172 x n
    that gives you x as 45
    Offline

    2
    ReputationRep:
    (Original post by vasuxx)
    yeah, much harder. I solved that one with ease this was a struggle
    A past paper or did you repeat ? I wish I had given it last year. 2015's past papers are hell easier.
    Offline

    2
    ReputationRep:
    (Original post by vasuxx)
    IT was very difficult :// I got the mean medium mode question, it was 78,78,76,and 68
    If that's the answer than I got the 78 part right. That does have marks, right?
    Offline

    16
    ReputationRep:
    (Original post by vasuxx)
    yeah, much harder. I solved that one with ease this was a struggle
    (Original post by emilyy_elizabeth)
    Honestly Maths was horrible I have done 30 past papers scoring A and above, no joke and this one was the hardest i've come across.
    (Original post by vasuxx)
    IT was very difficult :// I got the mean medium mode question, it was 78,78,76,and 68
    I feel for y'all :laugh:

    GL and keep your heads up! It'll feel like this for a while (Well, until results day... ), I felt the same but came out with an A*. All the best
    Spoiler:
    Show
    Please no one hunt me down if it turns out worse than expected
    Offline

    2
    ReputationRep:
    (Original post by MBamirny)
    This is how I did it:

    7.23(1 + 0.0114)^x = 10
    With x being the number of years.

    Through trial and error: when x = 28, the population is 9.930723215 billion. 28 + 2014 (January 1st) = 2042 January 1st.

    When x = 29, the population is 10.04393346 billion. 29 + 2014 (January 1st) = 2043 January 1st.

    This means that on the 1st of January 2043, the population was OVER 10 billion. That means the population hit 10 billion sometime between the 28th and 29th year after 2014. So it's sometime in 2042.

    X in the above equation is revealed to be 28.6133 (algebraically without trial and error), so it couldn't have been in 2043 when the population hit 10 billion because it's gone over by then. In fact if it's 28.6133 years after 2014, then it would be sometime in July of 2042, not 2043.
    The year is 2043 because the number of years A= 17.3(1+1.14/100) to the power of n. Then we were supposed to find n, and by using trial and error, the correct answer is 29. You add that to 14, and get 2043. Therefore, technically, by the year 2043 there are 10 billion people on earth.
    Offline

    2
    ReputationRep:
    (Original post by 15demon)
    If that's the answer than I got the 78 part right. That does have marks, right?
    Yeha that has 1 maark. The question was divided into the mean, mode, and the part where you subtract from 300 and get 68.
    Offline

    4
    ReputationRep:
    (Original post by Abdullah IGCSE)
    did you know the interior angle polygon question and the second nth term question?
    the nth term was 3^n-1
    Offline

    4
    ReputationRep:
    (Original post by loisclark9999)
    3^n+1
    3^n-1 ... sorry haha
    Offline

    2
    ReputationRep:
    (Original post by MBamirny)
    Isn't the answer to the question regarding the year when population equals 10 billion 2042? Using the compound interest formula, it'll take around 29 years or on January the 1st of 2043 for the population to reach OVER 10 billion (you get a decimal). Wouldn't that mean that the population REACHED the 10 billion mark the year prior? 2042?
    in the beginning 2042, the population is still in the 9 billions. Thats why it REACHES 10 billion in 2043, if that makes sense
    Offline

    2
    ReputationRep:
    (Original post by Imperion)
    I feel for y'all :laugh:

    GL and keep your heads up! It'll feel like this for a while (Well, until results day... ), I felt the same but came out with an A*. All the best
    Spoiler:
    Show
    Please no one hunt me down if it turns out worse than expected
    Hhahaha thanks so much Scared for paper4 if this was the outcome heree
    Offline

    0
    ReputationRep:
    (Original post by vasuxx)
    in the beginning 2042, the population is still in the 9 billions. Thats why it REACHES 10 billion in 2043, if that makes sense
    Yes, in the "beginning" of 2042 its in the 9 billion range. But no, it doesn't reach 10 billion in 2043, it reaches 10.0439... billion. Thats not 10 billion. This means that it reached 10 billion before the 1st of January 2043, which is in 2042.
    Offline

    2
    ReputationRep:
    (Original post by vasuxx)
    Yeha that has 1 maark. The question was divided into the mean, mode, and the part where you subtract from 300 and get 68.
    Yayy. !! Where did you find the solution? Send a link maybe.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: August 30, 2016
Poll
Do I go to The Streets tomorrow night?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.