Maths, Addmaths and Statistics: Post your doubts here!

[jj1234]

Hope this helps ^-^
for o'levels

 

[B!(+)(+)dy $k(_)!!]

 

[B!(+)(+)dy $k(_)!!]

 

[B!(+)(+)dy $k(_)!!]

 

[B!(+)(+)dy $k(_)!!]

 

[B!(+)(+)dy $k(_)!!]

 

[B!(+)(+)dy $k(_)!!]

The iii) part please.....!!

 

[Umna.Asim]

Someone please explain part C and D of question 15 to me. Thanks!

 

[Dark Destination]

Someone please explain part C and D of question 15 to me. Thanks!

Where's question 15?

 

[Umna.Asim]

Where's question 15?

Wait it's loading

 

[Dark Destination]

Wait it's loading

Alright..

 

[Umna.Asim]

Part C and D of Question 15 from the attached file.

 

[Dark Destination]

Part C and D of Question 15 from the attached file.

What's the value of x from part b(iii)?

 

[Umna.Asim]

What's the value of x from part b(iii)?

The answer is 5.72cm

 

[Dark Destination]

The answer is 5.72cm

The value of the height will be 2 times 5.72.

The new pyramid shaped candle will have half the height.

So the ratio of heights will be 1/2

The cube of that is 1/8.

So ratio of volumes will be 1:8

That means, the volume of a candle will be 1/8th the volume of the pyramid. The volume of the big pyramid is 125.

Divide that by 8, to get the volume of a candle. And Divide 125 by that. The answer is 8? 8 Candles?

 

[Dark Destination]

The answer is 5.72cm

For part D, they tell you that the cube burns down to 3 quarters of its original height in 20 mins.
That means 1/4th of its height burned.

You know the height of the cube. Multiply that by 1/4.. and that's the height of cube burned. Multiply the answer by the cross sectional area of cube (Original length squared). You'll get the volume of cube burned in 20 mins. The answer will be x.

x cm^3 --- burned in 20 mins.

y cm^3 --- burned in 30 mins.

Use ratio method, cross multiply.. and 30x/20 will be the volume of cube that would have burned in 30 mins.

Since the rate of burning of all candles is same.

The same volume of cylinder will be burned.

You know the radius of the cylinder, and it's cross sectional area (Pi r squared).

Pi r^2 * H = Volume burned in 30 mins

You can find HEIGHT.

 

[Umna.Asim]

The value of the height will be 2 times 5.72.

The new pyramid shaped candle will have half the height.

So the ratio of heights will be 1/2

The cube of that is 1/8.

So ratio of volumes will be 1:8

That means, the volume of a candle will be 1/8th the volume of the pyramid. The volume of the big pyramid is 125.

Divide that by 8, to get the volume of a candle. And Divide 125 by that. The answer is 8? 8 Candles?

For part D, they tell you that the cube burns down to 3 quarters of its original height in 20 mins.
That means 1/4th of its height burned.

You know the height of the cube. Multiply that by 1/4.. and that's the height of cube burned. Multiply the answer by the cross sectional area of cube (Original length squared). You'll get the volume of cube burned in 20 mins. The answer will be x.

x cm^3 --- burned in 20 mins.

y cm^3 --- burned in 30 mins.

Use ratio method, cross multiply.. and 30x/20 will be the volume of cube that would have burned in 30 mins.

Since the rate of burning of all candles is same.

The same volume of cylinder will be burned.

You know the radius of the cylinder, and it's cross sectional area (Pi r squared).

Pi r^2 * H = Volume burned in 30 mins

You can find HEIGHT.

Thankyouuu!

 

[Dark Destination]

Thankyouuu!

No Problem.

 

[hafsa saleem]

Hey plzzz can any1 help me solve this question.its a question frm 4024 june 2013 11.according to m.s the answer 2 the 1st part of q.16 is 4 .how??????plzzzz help me (urgently)

 

[***amd***]

Hey plzzz can any1 help me solve this question.its a question frm 4024 june 2013 11.according to m.s the answer 2 the 1st part of q.16 is 4 .how??????plzzzz help me (urgently)

The answer is 44, not 4.