Hi everyone,

These are just the answers. I'll to post worked solutions later. Sorry for the delay. There's now a rule which says that teachers can get the papers 2 hours after starting. Last year it was 30 minutes.

Anyway ... for the record ...

**Section I**

1. A

2. D

3. B

4. C

5. B

6. B

7. D

8. C

9. C

10. C

11. A

12. B

13. D

14. A

15. A

16. C

17. D

18. D

19. B

20. C

21. B

22. B

**Section II**

**Question 23**

(a) 4ab/3 **i dont noe bout this one, but rnt we meant 2 make the denominators the same, which will give = 3a6^3/3bw X 4w^2/3bw = 12ab^3w^2 ??? because denominator cancels out since theyr the same...**

(b) (i) 19*C

(ii) February

(iii) August **its asking in monthS = so its from may to september**

(c) (i) Systematic sample, something like every 5th student in order on the roll. **it can also b stratified**

(ii) Mean is 7.275 hours per week (using class centres). Mean class is 5-9 hours per week.

(d) (i) $6

(ii) 4 kg or 7 kg

(iii) Weights more that 4 kg, up to and including 6 kg, and weights more than 7 kg.

(iv) $1.50 per kg

**Question 24**

(a) Vertical axis does not start at 0, pictures change in three dimensions instead of just one. **also, scale of boxes are inacccurate = creates bias**

(b) (i) 71* **its 70***

(ii) 109 cm

(c) Lovely box plot, Min = 140, Q1 = 145, Median = 150, Q3 = 170, Max = 190

(d) (i) 567 L

(ii) 30 cm **this isnt correct. d answer is 15cm... y did u X2? the trough is only ***d* cm long... thats it

**Question 25**

(a) (i) 6

(ii) 1/3

(iii) 2/3

(b) (i) 28 days

(ii) $8.61

(c) (i) 1/60

(ii) 1/5370

(d) Martha's effective interest rate is 6.36%p.a. so Paul gets the better deal.** i actually put them all into an annuity formula (with the same principal) and martha's one was higher, and i also double checked...???**

**Question 26**

(a) (i) Lovely diagram

(ii) 53 m

(b) (i) Lovely net - probably best is to have four lots of a triangle on top of a rectangle next to each other across the page.

(ii) 252 m^{2}

(c) (i) 98

(ii) 43/100 **??....its 74/200 = 37/100**

(iii) 28

(d) 17 h 30 min

**Question 27**

(a) (i) $130 000 over 30 years** .. also incorrect... max is $80 000 over 10 years.**

(ii) $45964.80

(b) (i) y-intercept exists when height = 0 cm, but this will never occur. No person ever has a height of 0 cm.

(ii) George's feet should be 3 cm longer than Harry's

(iii) For this data, correlation coefficient should be positive rather than negative. Correlation coefficients only range from -1 to 1 so r = -1.2 is not possible.

(c) (i) $24000

(ii) $7593.75

(iii) Graph - Straight line from $30000 to $24000 after 3 years, then curve down to $7593.75 after 7 years

**Question 28**

(a) (i) 4 combinations: 1 x $2, 1 x 50¢; 2 x $1, 1 x 50¢; 1 x $1, 3 x 50¢; 5 x 50¢

(ii) 6/55

(iii) $(2*x* + *y* + 0.5*z*)

(b) (i) $12

(ii) $17 500** which is 3500 vehicles**

(iii) *v* = 6000 – 500*d*

(iv) Anne's statement is incorrect. Maximum daily income is $18 000 when the toll is set at $6 per vehicle.