2007 section 2 PROBLEMS ,HELP PLEASE! (1 Viewer)

[Crazywheels]

Questions From
23c ii
Calculate the estimate for the total population of crocodiles in this area??

25c iii
Calculate the probability that grant chooses two dvds with the same rating??

26a iii
calculate the bearing of town Q from Town B??

Thankyou



Link to exam paper

http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/index2.html

 

["UserNamE"]

Hey, this is what i get -

23cii - N = 45/18 x 24
= 60

25ciii - 1/3 x 1/3 = 1/9

26aiii - 180 - 149 = 31
87 - 31 = 56
180 + 56 = 236 , therefore bearing of q from b is 236 degrees

umm i think thats right but im not 100% sure, doesn anyone else get those answers?

 

[PC]

23c ii
Calculate the estimate for the total population of crocodiles in this area??

Let n be the population of crocodiles.
So 24/n = 40/100
40n = 2400
n = 60
So estimate is 60 crocodiles.

25c iii
Calculate the probability that grant chooses two dvds with the same rating??

It helps to have the tree diagram filled out with probability on all the branches. I always go through and work out all the possible probabilities then I can just read off the answers.

P(same rating) = (5/10 x 4/9) + (3/10 x 2/9) + (2/10 x 1/9)
= 2/9 + 1/15 + 1/45
= 14/45

26a iii
calculate the bearing of town Q from Town B??

You really need a diagram to look at here, with as many angles filled in as you can.

Bearing = 180 + 56 = 236°

 

["UserNamE"]

woops screwed up the 2nd question, didnt read the top part just (iii

 

[Crazywheels]

Thanks

Also does anyone know answers to
27 b,iii


And C ii on simpsons Rule
????
Thanks

 

[PC]

Also does anyone know answers to
27 b,iii

From (ii) you have d = 0.031

Now the new cost equation is $6 to buy each light bulb, then $0.031 per hour.
If the bulbs are now running at 10 hours per day, 365 days per year, then the cost for 4 light bulbs is:
Cost = 4[6 + 0.031 x 10 x 365]
= $476.60
So the cost does not double.

Alternatively:
From (i) you have C = 24 + 7300d
You can double the running costs (the 7300d bit), but the cost of purchasing each light bulb won't double (the 24 bit). So the total won't quite double.

And C ii on simpsons Rule
????
Thanks

From (i) you have Area of the cross section as 50.4 cm².

Now area of base (rectangle) = 14.4 x 200 = 2880 cm².
Area of side (rectangle) = 5 x 200 = 1000 cm².
(Look out for the different units, 2 m = 200 cm.)

So area of Curved Surface = Total SA – (Area of Base + Area of Side + 2 x Area of Cross section)
= 7480.8 – (2880 + 1000 + 2 x 50.4)
= 3500 cm².

 

[Crazywheels]

And how do you get that decimal answer for b ii in the question on light globes
thanks

 

[Crazywheels]

HElP PLEASE URGENT!!

 

[PC]

HElP PLEASE URGENT!!

Don't panic! Really important. Stay cool.

The total cost of running the light bulbs is
Cost = 4 x [6 + d x 5 x 365]
= 4 x [6 + 1825d]
= 24 + 7300d

So when the cost is $250, we have:
250 = 24 + 7300d
226 = 7300d
d = 0.031