MATH IGCSE HELP....URGENT PLEASEEEE

[Fatima18]

I can't understand these questions.Hope someone can help with it.Thanx!
May/June 2010 varient 22-------number 8b and 16
May/June 2010 varient 23-------number 14 and 22
May/June 2011 varient 21--------number 20b
Oct/Nov 2011 varient 23---------number 14
Oct/Nov 2010 varient 23---------number 13 and 18

 

[CaptainDanger]

May/June 2010 23
14)
3 (y - 4) + y/2 = 9
3y - 12 + (y/2)=9
(6y-24+y)/2=9
6y-24+y = 18
7y=42
y=6

22)


May/June 2011 21
20) b)

f g(x) = 125
f (2x-3) = 125
f(x) = x^3
==> f (2x-3) = 125
(2x-3)^3 = 125
2x-3 = 5
x = 4

 

[Fatima18]

May/June 2010 23
14)
3 (y - 4) + y/2 = 9
3y - 12 + (y/2)=9
(6y-24+y)/2=9
6y-24+y = 18
7y=42
y=6

22)
View attachment 17119

May/June 2011 21
20) b)

f g(x) = 125
f (2x-3) = 125
f(x) = x^3
==> f (2x-3) = 125
(2x-3)^3 = 125
2x-3 = 5
x = 4

Thanx a lot

 

[CaptainDanger]

Oct/Nov 2011 23
14)
Volume of sphere = (4/3)π r^3

Volume of cylinder = πr^2 x height = πr^2 x 2r

(Volume of sphere/ Volume of cylinder) x 100 % = Answer

Oct/Nov 2010 23
18)

Note that 16 comes from the radius added into the perimeter. When you use the formula its just the arc length.
(x/360)2π8 = 14π
Solve.

 

[niddhi]

I can't understand these questions.Hope someone can help with it.Thanx!
May/June 2010 varient 22-------number 8b and 16
May/June 2010 varient 23-------number 14 and 22
May/June 2011 varient 21--------number 20b
Oct/Nov 2011 varient 23---------number 14
Oct/Nov 2010 varient 23---------number 13 and 18

May June 2010 varient 22 question 16:
0.5*(a+b)*h=0.5*b*h
0.5*(10+16)*10=0.5*16*h
26*5=0.5*16*h
130/0.5=16*h
260/16=h
16.25=h
Sorry but idk question 8b...well gud questions though