Discussion and Suggested Solutions - General Maths 2017

[Potatohater]

is 28bii. really 40%?? I got that at first but then I realised it was 1/5  (20%) because if one person had a 40% probability of being included then the other four people must somehow be less likely to be chosen?

It's because there are 2 spots so you would work it out by doing (1/5 X 4/4) + (4/5 X 1/4) = 2/5

[executivewaddlez]

In Question 29A (ii), I believe the correct answer is 11mm. 2km squared is miscalculated.

[jonty.y]

It's because there are 2 spots so you would work it out by doing (1/5 X 4/4) + (4/5 X 1/4) = 2/5

I get that but you could do that calculation for each person, thus each person has a 2/5 chance of being picked,

2/5 = 0.4
0.4 x 5 (five people) = 2
and probability can’t exceed 1??

[erhulloollie]

I get that but you could do that calculation for each person, thus each person has a 2/5 chance of being picked,

2/5 = 0.4
0.4 x 5 (five people) = 2
and probability can’t exceed 1??

just to make it maybe a bit clearer or maybe worse....
if you write out all the different pairs: AB, AC, AD, AE, BC, BD, BE, CD, CE, DE....then lets take Alice (A)... coz i cant remmeber the girls name.. maybe it was emily anyway it doesnt matter, she is in 4 pairs out of 10 therefore 4/10 = 2/5.....
hope it helps if not too bad... i got this question wrong too.. i did 1/5 just learn from your mistakes.. or just forget about it coz we NEVER have to do maths again....!!

[jamonwindeyer]

gee, you just did the genny maths paper and now you're gonna do the 2u paper. what a beast!

Thanks for doing this!! 

I feel absolutely wrecked  - But it was a good time

i found the exam really challenging... seemed A LOT harder than any of the past papers i did!!! 
also i can't seem to view any of the answers?!?...  it just comes up with a square which is really annoying!! 

Are you able to see them now? Maybe it took a while to refresh/load for you? Our site is under heavy strain so it could be a little slow

Question, if for the cone one, it turns out you actually accidentally worked out the volume correctly and it's in your working but thought you had to minus the sphere from it and hence tried it that way and gave and therefore equals 'utter bullshit' answer, would I still manage to get the marks for the question?  Or because I gave a therefore different crap answer I'll lose marks?  Thanks

I reckon you'll probably lose a mark out of the 3 for misinterpretation, but they could be nice and give you full! Either way, definitely 2/3

is 28bii. really 40%?? I got that at first but then I realised it was 1/5  (20%) because if one person had a 40% probability of being included then the other four people must somehow be less likely to be chosen?

There is overlap, because other people would be included in the teams with that person! Definitely 40%, list them and see!

[jamonwindeyer]

In Question 29A (ii), I believe the correct answer is 11mm. 2km squared is miscalculated.

Hey! I'm fairly certain I'm right there, 2 square kilometres is  2,000,000 square metres right? Like, 1 square kilometre is 1000x1000=1,000,000, so two of them would be double?
Can anyone still not see solutions? I really hope everyone has been able to see them now

[pepepeepe]

A mark of 86 is guaranteed band six right?

[jamonwindeyer]

A mark of 86 is guaranteed band six right?

Never guaranteed, but I'd say highly likely

[Microsoft Word]

For the cone question: i assumed the radius of the cone base was 4cm. I carried on found the height to be 9 and inputed everything into the volume formula. I just forgot to use pythagorus to find the true radius. Is that 3 marks gone?

[jamonwindeyer]

For the cone question: i assumed the radius of the cone base was 4cm. I carried on found the height to be 9 and inputed everything into the volume formula. I just forgot to use pythagorus to find the true radius. Is that 3 marks gone?

You'll probably only lose one mark!

[Trashzikie]

For q11, I got the PV formula and made R the subject and got 22%, did I over complicate it?

[jamonwindeyer]

For q11, I got the PV formula and made R the subject and got 22%, did I over complicate it?

I think this will get you the depreciation as a fraction of the new price, rather than the original as requested!

[pepepeepe]

For question 21, why is this wrong?

30.50 x 100 = 3050cm
3050 - 0.5 = 3049.5cm
3049.5 / 100 = 30.495cm
Thus, answer is C

[dub192]

For 28c, I did three months interest because i thought he paid the repayment after the second month, so first months interest with no repayments and finished with three months interest and two repayments, pretty sure working is still correct, would i just lose one mark?
For 28a ii, i said that Fahrenheit equals to Celcius because it asked to refer to the graph for F = C, could that be right?
For 28 b ii is 2/5 fine?
30 e (cone), i worked out the correct volume but i over complicated the question and tried to find out how much the sphere was taking out, so would that be another mark lost?

[Juliesokha]

Hi,
um for example I did my solutions wrong but the formula and stuffs were right..and say it was a 3 mark question..would they at least give me 1 or 2 (for almost like 90% getting the correct answer?)