Feedback on Paper 1 Mini-mock

I have just finished correcting this.

Most students handled the long division very well.

However most students failed to write 44100 as a product of its prime factors. Look back in the early chapters of the yellow book for how to do this.
Prime numbers are 2,3,5,7,11 etc
Start dividing 44100 by primes,
2 ⌊44100
2 ⌊22050
3 ⌊11025
3 ⌊3675
etc
Then list all the factors as 2x2x3x3x5.... etc

The scientific notation was well done.

The tax question could have been better laid out in a few cases. Make sure that you don't just write down a jumble of numbers. Also, check what you are asked for: in this case it was net income, not net tax.

The factoring was well done but a few of you couldn't figure out how to factor
6x² - 7x - 24
and resorted to the quadratic formula.
This is an acceptable "cheat" as long as you realise that
a) you were given an expression to factor not an equation to solve and
b) you take the "roots" of the "equation" and convert them back into factors.
For example:, you should have ended up with x = -1.5 as one of your "roots".
Working on this:
x = -1.5
2x = -3
2x + 3 = 0
So (2x + 3) is one of the factors you are looking for.
Do the same for the other "root" and write down your answer as if you hadn't used the quadratic formula (covering your tracks)
6x² - 7x - 24
= (2x + 3)(3x - 8)

On the Sets questions, lots of you lost marks because you didn't show enough work.
If you are asked (A\B) ∪ (A ∩ C)
then write down the solution set of (A\B) first, then the solution set of (A∩C), then the final union of both sets.

The solving for y using a Venn diagram question was reasonably well answered. A few of you left out the 4 people who hadn't visited any of the countries when calculating y.
Another common error was to not answer the last part of the question (how many people visited 1 country only), throwing away 5 marks.

On the functions question, lots of you answered using trial and error. After all those years of practicing solving quadratic trinomials by factoring, this was an opportunity to apply that know-how.
The quadratic function was of the form x² + 2x - 8 and you had to find the two values of x for which the output of the function = 0.
In other words, solve:
x² + 2x - 8 = 0
(x + 4)(x -2)=0
x = -4, 2
(This kind of questions goes to the very core of understanding functions. The fancier those calculators get, the more you will see questions like this on the exam!)
BTW, we are not finished yet. Lots of you lost marks because you didn't pay attention to the detail of what you were asked for: the co-ordinates of a and b. If you don't write down (-4,0) and (2,0) you lose marks.
For finding the intersection with the y-axis at c, you need to recognise that the input into the function at this point is x = 0.
Sub in x=0 and solve.
f(x) or y = 0² + 2(0) - 8 = -8
So the co-ordinates of c = (0,-8).
Finally, the last part of the question (which several students left out) asked for the range of values for which f(x) ≤ 0
As you were told x ∈ R, it isn't enough to write down: -4,-3,-2 .... etc.
You have to write it as -4 ≤ x ≤ 2

Overall, the results were pretty good, given the rush. Make sure that you know where you went wrong. We will go over paper 1 issues tomorrow and do a paper 2 mini-mock on Wednesday.