IGCSE MATHS Doubts

[haris94]

it is the same actually

[Vin]

sorry nets really responding slow .. !!  

im not quite sure about Q11 n Q14(b) .. they dont match my answers from the ms..  

19 b)

9999 = 10⁴ - 1
theres a rule (a² - b²) = (a+b) (a-b)
so, (10² + 1) (10² - 1)
now if u notice (10² - 1) also falls under the above rule ..

(10² + 1) ( 10 +1) (10-1)

101 x 11 x 9

they hav asked 'as a product of prime factors.'
so tht would be

101 x 11 x 3 x 3

Q22 (b)

if u see it forms a right angled triangle
OA and AB are 15 each .. thrice p/w

so by Pythagoras ..
OBsup]2[/sup] = 5²+5²
OB = 21.2

[Fastal]

14b

x=230 and 310.

continue the sine curve on theleft side of the graph they gave. this tells you that the curve from 0 to -180 is the same as from 360 to 180

thus 360-50
and 180+50

11b-dont really understand

[Adzel]

14b

x=230 and 310.

continue the sine curve on theleft side of the graph they gave. this tells you that the curve from 0 to -180 is the same as from 360 to 180

thus 360-50
and 180+50

11b-dont really understand

I did the same thing but the mark shcheme said its wrong...

[Adzel]

OA and AB are 15 each .. thrice p/w

I did not understand this part...

[Vin]

I CANT FREAKING POST ANYTHING !! wats wrong wid SF freeexampapers they r too slow.. ?? all other websites run normally .. prob with server/bandwidth ??

[Vin]

I did not understand this part...

If u see OA is actually 3 times p tht is
OA =OP + PQ + QA
OA = 5+5+5
=15

n same for AB

AB= AR+RS+SB
= 5+5+5
=15

..

[Fastal]

I did the same thing but the mark shcheme said its wrong...

can you post the marking scheme, i cant find it

[haris94]

17 (a) In 2007, a tourist changed 4000 Chinese Yuan into pounds (£) when the exchange rate was
£1 = 15.2978 Chinese Yuan.

Calculate the amount he received, giving your answer correct to 2 decimal places.

(b) In 2006, the exchange rate was £1 = 15.9128 Chinese Yuan.
Calculate the percentage decrease in the number of Chinese Yuan for each £1 from
2006 to 2007.

someone tell me how to do "b" part and please explain
Thanks

[astarmathsandphysics]

should be no probs. I will contactsupport - we have 1 MBPS more bandwdth form this morning - 3MBPS in total at the moment

[astarmathsandphysics]

(15.9128-15.2978)/15.2978*100
(new-original)/original*100%

[Fastal]

17 (a) In 2007, a tourist changed 4000 Chinese Yuan into pounds (£) when the exchange rate was
£1 = 15.2978 Chinese Yuan.

Calculate the amount he received, giving your answer correct to 2 decimal places.

(b) In 2006, the exchange rate was £1 = 15.9128 Chinese Yuan.
Calculate the percentage decrease in the number of Chinese Yuan for each £1 from
2006 to 2007.

someone tell me how to do "b" part and please explain
Thanks

percentage decrease=old value-newvalue/oldvalue*100

so here

%=0.615/15.9128*100
thus % decrease=3.86%

[Adzel]

so by Pythagoras ..
OB = 5²+5²
= 21.2

And you wrote this  

[Adzel]

can you post the marking scheme, i cant find it

Here you go..see it by your self 

[Malak]

Nov 05 P2

Q: 20 part b

thx