# 3Unit Mathematics 2007 Solutions (1 Viewer)

#### bobbytrac2222

##### New Member
defaultPlayer said:
mm question 5b .. did you have to add in 2! for the parents..

it asks what is the probability tat the 4 children are allocated seats next to each other? .
yea you have to add 2! coz da parent can change position while the children are next 2 each other, which counts as one combination

#### jah_lu

##### Member
dont think of it as adding 2! to the parents
think of it as
you have 3 people (let the children be one group)
so 3! ways of arranging them
inside the group of children, you can arrange them 4! ways
therefore 3!4! possible arrangments

#### arwin

##### New Member
AMorris said:
All right I think, numerically at least (and ur integration for 1e is correct) apart from the very last question. the greatest range in the secodn interval will be achieved when m = 1 so the range should be 19.51 <= x <= 20 and the width should be .49.
dammit morris! u just ruined my hope of getting 84 haha didnt see that at all, i sort of thought it was suspiciously easy for a last question but no way i wouldve thought of that during the exam. what the hell man, hope ur the only person who've thought of that!

#### AMorris

##### Member
Don't worry - I didn't see the widths part of the question so I only put in the interval. I haven't heard about anyone yet who hasn't lost some mark somewhere so you never know - top mark may be 83 (or 83.5 if they give out half marks)

#### jah_lu

##### Member
they neva give half marks in hsc
and yeh i only know of 2 people who got it
morris and some fort st guy (even terry lee didnt notice it so dont worry about it)
isn't it weird though
when you have heaps of people claiming full marks in 4u and not in 3u
guess that shows how easy the 4u test was
now wishing i worked a bit faster and finsihed the test

#### qazwsxedcrfvtgb

##### New Member
haha yess i was waiting for someone to say that!
i got 0.49m as well

guess ill be seeing you in a bit over a month morris!
premiers luncheon here we come

#### AMorris

##### Member
qazwsxedcrfvtgb said:
haha yess i was waiting for someone to say that!
i got 0.49m as well

guess ill be seeing you in a bit over a month morris!
premiers luncheon here we come
Nicely done - unfortunately I misread the question and only put the ranges instead of the widths, and I didnt top internally so I doubt I'll be getting an invite.

#### arwin

##### New Member
AMorris said:
Nicely done - unfortunately I misread the question and only put the ranges instead of the widths, and I didnt top internally so I doubt I'll be getting an invite.
ohh no way thats so unfortunate hey

#### sja

##### dingleberry
fishy89sg said:
sorry for the repear double post, but based solely on your solutions, and assuming i get part marks for working, i should get:

Question 1: 12/12
Question 2: 9-10/12
Question 3: 11/12
Question 4: 11/12
Question 5: 11/12
Question 6: 11/12
Question 7: 10-12/12

= 75-78/84

Damn........... stupid errors
Wow, you're one fucking nerd!!

#### 2syllables

##### Dango Daikazoku
sja said:
Wow, you're one fucking nerd!!
not really a nerd would be getting 83,84