# Recent content by mathpie

1. ### ATAR estimate after trials

Accelerated HSC marks: Extension 1 maths(2016): 100/100 Extension 2 maths(2017): 100/100 Internal trial marks + overall rank in school ranked around 300th: English advanced: 98/100 | 1st Chemistry: 96/100 | 1st Physics: 89/100 | 1st Could someone work out an ATAR estimate for me...
2. ### gravimetric analysis help

Question: To determine the sulfate concentration in a liquid fertilizer (aqueous solution), an analyst first diluted 50 mL of the fertilizer solution to 250 mL, pipetted out 25 mL of the dilute solution, added 200 mL water to it then precipitated the sulfate with barium nitrate solution. The...

4. ### trial question help

Could someone please explain why the answer to this question is C?
5. ### challenging gravitation question #2

Hi, I'm struggling to understand the solution to this question. could someone please explain the steps attached.

7. ### BoS Maths Trials 2017

what schools came to the top?
8. ### ICAS problem

Icas results are out online, and only 20% answered this problem, which seems relatively easy at first, correctly: Mary had 3 identical cubes. each cube has one pink face and one yellow face. the rest of the faces were blue. she joined the cubes as shown to form a solid (3 cubes connected in a...
9. ### Sydney Grammar 2009 help

I've attached the question I don't understand. specifically, I don't understand the 3rd line of the solution, which states there is a double root at the y-coordinates of the stationary points? is that a rule where y-f(x) = 0 has a double root at y=f'(x)??
10. ### 2002 HSC help

Hi, this is Question 7 b from the 2002 HSC. I could do parts (i) - (iii) pretty easily but I'm struggling with (iv). I understand the solution up until it says "so OP3 = |z4| = 1". How do they know that OP3 = 1?? Also, can the exterior angle sum of a polygon be 4pi, 6pi, etc and not just 2pi...
11. ### 1967 HSC help

This is only the first question of the 1967 Extension 2 HSC and I am already having trouble. Pls help. Are there solutions to these older papers (<1991) online??
12. ### AMC

what did everyone get for the last 5 (free response) questions in the senior division?
13. ### Australian Maths Competition

Re: Westpac Maths Comp marathon What did everyone get for the last 5 (free response) questions in the senior division? I couldn't get any.. lol
14. ### James Ruse Trial Help

This question is from the 2006 4U JRAHS Trial. I got part a) but for part b), my answer is 71'34'. I am confused about their solution and think it may not be correct. Could someone clarify please? My solution gave that the truck starts at x=V^2sin(2theta)/3g, where y = the focus =...
15. ### Physics help

for d1, doesn't sound first travel to the wall and then back to the observer? so 80+80+240 = 400