IGCSE starting on Friday... pls.post doubts, important notes etc.

[Min Thaw]

um..so it means only point A and B
thanks for your explanation

 

[Stancy Motha]

2cm all around the line AB
2 parallel line one on the top and another at the bottom and two semicircle on the left and right. It forms a complete shape around line AB.

 

[Stancy Motha]

Here are sum good revision books:

 

[Stancy Motha]

1)Write down the next two terms of the sequence
1, –4, 9, –16, .............., ..............,
2)A water tank is a cuboid with dimensions 40cm by 90cm by 70cm. The tank is initaially empty and is then filled with water which flows from a pipe of cross-sectional area 1.2cm^2 at a speed of 3.5m/s.Calculate the time,in minutes,that it takes to fill the tank completely.

 

[Min Thaw]

25, -36

10min

 

[Min Thaw]

Volume of cuboid = 40*90*70=252000cm^3
Volume of water flow per second = 1.2 * ( 3.5*100) =420cm^3 ( because 3.5m = 350cm)
Therefore time taken = 252000/420 =600s/60 = 10min

 

[Stancy Motha]

1)On 1st August 2005, the value of a car was £12 600.
On 1st August 2006, the value of the car had decreased by 10% of its value on 1st August
2005.
On 1st August 2007, the value of the car had decreased by 5% of its value on 1st August
2006.
Express the loss in the value of the car over the two years as a percentage of its value on
1st August 2005


2)In a school there are 792 pupils, 58 more girls than boys. Calculate the number of boys in the school

 

[Min Thaw]

A car travels from X to Y at an average speed of 60km/h and returns to X at a speed of 40kph. what is its average speed for the whole journey?

 

[Min Thaw]

14.5 %

367

 

[Stancy Motha]

50 km/hr

 

[Min Thaw]

no that's not the answer... the answer is 48 km/hr

 

[Stancy Motha]

1)The length of tw0 peices of wood are in the ratio 9:5.The length of the shorter peice of wood is 45.2
Calculate the length, in cm, of the longer peice of wood.

2)An equation for each of four straight lines is as follows:
y=3x+4
y=2x+3
y=4x+3
y=4x+4
(a)Write down the equations of the two lines that pass through (0,3)
(b)Write down the equations of thr two lines that have the same gradient.

3)One angle of a quadrilateral is 100° and the sizes of the other three angles are in the ratios
1:3:6. Calculate the sizes, in degrees, of the other three angles.

4)A right circular cone has height 12 cm and base radius 5 cm.
(a) Show that the curved surface area of the cone is 65 π cm.

5)A coin is biased so that the probability of throwing a tail is 1/5
The coin is to be tossed three times.
Calculate the probability of
(a) throwing two heads followed by one tail
(b) throwing two tails and one head in any order.

6)Each edge of a cube is of length 3 m. The edges are increased by 20%.
Calculate the percentage increase in the volume of the cube.

7)The length of a road is 1.2 km. On a map, the length of the road is 3 cm.
Express the scale of the map as a ratio in the form 1 : n, where n
is a positiveinteger.

8)The size of each interior angle of a regular polygon exceeds the size of the exterior angle by 140 degrees.
Calculate the no of sides of the polygon.

 

[Min Thaw]

1. 81.4
2.a. y = 2x+ 3 and y = 4x+3
b. y = 4x + 3 and y = 4x +4
3. 26, 78, 156
4. pi*5*square root of (12^2+5^2) = 65 pi
5.a. 16/125
b. 12/125
6.72.8%
7. n= 40000
8.i think something wrong " both interior " ?!

i got n in decimals @_@

 

[Stancy Motha]

A nythin for me??

 

[Min Thaw]

well..i think my sis not coming online..
i'll explain : let "m" be the time take to X to Y
so distance = m*60 = 60m

time taken for return = 60m /40

average speed = 120m/[m+60m/40]
= 120m/(100m/40)
= 48kph

 

[Min Thaw]

pls explain me about the no.8 ..i can't solve it..n = in decimal

 

[Stancy Motha]

pls explain me about the no.8 ..i can't solve it..n = in decimal

sorry dude typing mistakeeI edited the mistakes...I bet u can do it now anywayz
interior angle (i)
exterior angle (e)
i + e = 180
i - e = 140....(e-e )
2i =320
i = 160
180-160 =20
360/20 =18 sides

 

[Stancy Motha]

A small department store sells only household goods, furniture and clothing. In a pie chart
showing the sales, in £, of these for Monday, the angle for household goods is 120° and
the angle for furniture is 100°.
Given that the store sold £480 of household goods on Monday,
(a) calculate the sales, in £, of furniture on Monday,
(b) calculate the sales, in £, of clothing on Monday.

 

[Min Thaw]

400
560

 

[Stancy Motha]

WE HIT 100 comments
OOH-LA-LAH

Jan 2010 q. 29
cud u solve
gce o-level