Exams are getting easier right?
I made a comment on the Shuttle site on this blog entry and in it posted some of the easier questions from the GCSE paper done by the Radio 1 DJs. No-one yet seems keen to have a go so I'll post the questions exactly as presented by the exam here. No calculators allowed (not that you should need them)
- 10 (b) (i). Factorise x2 – 13x + 30 (2 marks)
- 10 (b) (ii). Hence, solve the equation x2 – 13x + 30 = 0 (1 mark)
- 15. Evaluate 5–2 × 1000.5
Write your answer in its simplest form. (3 marks) - 18. Leonardo is revising for his Higher tier GCSE Mathematics exam.
He comes across this question …
Two events A and B are independent.
The probability of B is double the probability of A.
The probability of both A and B occurring is 9/32
Find the probability that event A occurs.
Complete Leonardo’s solution.
Let the probability of event A occurring = p
therefore, the probability of event B occurring = 2p (3 marks)
[Update - for the entire paper in PDF format here it is]
6 comments:
Well, at the risk of ridicule.
10(b)(i) (x-10)(x-3)
10(b)(ii) x=10 or 3
15. 2/5
18. 3/8
Bit rusty but I did A level Maths 40 years ago, so I suppose I may qualify as one of your mathmos.
I consider all questions fairly simple but as there were no probability or statistics in my curriculum I had to engage brain a little for the last question.
I have not looked at the link you gave (in case the answer was there). What was the average of correct answers?
Andrew
{applause} 100% correct; although I'd have arranged the equation (x-3)(x-10) :-P
The required marks for each grade were-
A* - 65%
A - 51%
B - 38%
C - 26%
For the eight Radio One DJs who took the test the results were
Carrie Davis - 28% C
Aled Hadyen Jones - 19% Fail
Dave Vitty - 14% Fail
Jenna G - 12% Fail
Greg James - 7% Fail
Dev - 1% Fail
Scott Mills - 1% Fail
Nick Grimshaw - Nil Fail.
To put it another way by just answering those 4 questions correctly (subject to marks for working out) you beat four of the above with just 9%.
I've just updated my entry with a link to the full paper if you want to have a go.
I want to know who your at least two mathmos are. I'll have you know I attained the awesome grade of U at both STEP Maths II and STEP Maths III. I'd probably get half marks at all of your questions: I could write down the answers but would never be able to remember what working-out you're supposed to show.
FTR, my brother did his GCSE maths this year and got an A. As for the self-referential probability question, Cambridge Mathematical Tripos papers are always like that. The Ia probability question is always something like "The Ia Maths examiner grades papers by throwing them down a staircase. Landing on the first step is a fail, landing on the second step gets a gamma, on the third step a beta, and on any other step an alpha. Given that the initial velocity is normally distributed according to blah blah blah, what fraction of students get alphas?" Even in computer science, I remember in my year the Ia probability question was on distributing exam results to students' pigeonholes, and given that Cambridge uses anonymous candidature, how many students can expect to receive a better mark than the one their paper got.
Well I was kinda thinking of you and Invisible, guess I'll have to change that thought :-)
Heh even if you did get only half marks for that question snippet you'd still beat three of the DJs.
I do like that probability question I bet there are those who think that represents current marking methods.
Question: How do you factorise equations?
(Seriously, I have no idea how you're supposed to do this…)
FWIW, I failed epically with #15.
Okay for an equation of type x^2+bx+c you split into (x+m)(x+n) where m+n=b and mn=c. So for q10b(i) we need two numbers that when added together equal -13 and when multiplied equal 30; -3 and -10 or +-2 and -+15. As it's -13 and +30 we need two identical signed values so -3 and -10.
For q15 a negative power is the inverse of the positive power so 5^-2 is the inverse of 5^2; 25 so 1/25. Fractional powers you power by the numerator and root by the denominator. So for 100^0.5 we rewrite it as 100^1/2. 100^1=100 and the square root of 100=10.
So the question can be rewritten as 1/25*10 or 10/25; in simplest form 2/5.
Now you know that, and just for fun, try 32^-2/5
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