maths MC !! help urgent

26) The answer is C
The required probability
=(12C1*40C1+12C2)/(52C2)
=7/17

32) The answer is C
By using triangle inequality,
AC+BC>AB
4x+(3x-2)>8
7x>10
x>10/7

When x=6
AC=4x=4*6=24
BC+AB=(3*8-2)+8=24
By using triangle inequality,
BC+AB>AC
However, in this case, BC+AB=AC, which is impossible
Therefore x<6 and x>10/7
i.e. 10/7<x<6

35) The answer is A

In the graph of x>=2 and x<2
Two areas do not overlap
i.e. no solution

In the graph of x>=-2 and x<=-3
Two areas do not overlap
i.e. no solution

In the graph of x>=6 and x=<7
Two areas do overlap
i.e. 6=<x=<7

I and II is true

37) The answer is C

For A,
When x=3, y=9
3k1=9
k1=3

When x=5,y=15
5k2=15
k2=3

When x=6, y=18
6k3=18
k3=3

When x=12,y=36
12k4=36
k4=3

Therefore the equation should be y=3x, which is incorrect in this case

For B,
When x=2,y=4
When x=3,y=9
When x=6,y=36
When x=8,y=64
Therefore y=x^2, which is also incorrect in this case

For D, It is incorrect too since y is inversely varies with x
So When x is increased, y is decreased

38) The answer is B

From the graph,
-2<y-x<1
By dividing the inequality by -1,
-1<x-y<2

39) The answer is A
Considering one smoker is drawn,
The combination of drawing any 2 people = 15C2 = 105
The combination of drawing one smoker and one non-smoker = 11C1*4C1 = 44
The required probability= 44/105

Alternative method
The required probability = (11/15)*(4/14)+(4/14)*(11/15) = 44/105

40) The answer is D

The shaded region of 6x-y+3=<0 is region III + region IV
The shaded region of x-y+2=0 is region I + region IV
Considering the equation,
two regions overlap in region IV
Therefore region IV is the answer

41) The answer is D
The equation is y+x=0 since y=-x
the shaded region is y+x<0
Therefore y<-x

42) The answer is C
I is incorrect since the shaded region lies below x-y=-2
Therefore, it should be x-y=<-2 instead

II is correct since the shaded region lies above 2x+3y=1
Hence, it is 2x+3y>=1

III is correct since the shaded region lies above 6x-y=20
Thus, it is 6x-y>=20

2013-06-18 14:00:07 補充：
C in no.26 and 39 mean "combination" instead of "choose".
In your calculator,
u need to press the buttom in the way as follow:

[(][1][2][shift][÷][1][X][4][0][shift][÷][1][+][1][2][shift][÷][2][)][÷][(][5][2][shift][÷][2][)]

2013-06-18 14:00:16 補充：
In order to have the symbol "C", u need to press [shift][÷]

I think the use of combination will be taught in F.5 Chapter 4 and 5.

if you do not learn about C, you can try this.
the required probability
=P(1 face and 1 other) + P(2 faces)
=2(3/13)(40/51) + (3/13)(11/51)
=7/17