Tutor MathsGuru: Ask me for your burning Maths questions!

[Andrew Lee]

MathIzzzFun:

Andrew Lee:

In 2008, the enrolement of Jing Tao Primary School was 60% that of Shu Quan primary School. In 2009, 120 pupils left Shu Quan Primary School. In the end, the enrolment of Jing Tao Primary School was 80% that of Shu Quan Primary School in 2009. What was the enrolment of Jing Tao Primary School in 2009 ? :idea:

Hi

Number of pupils in Jing Tao remained the same in 2008 and 2009.

In 2008, ratio of pupils in Jin Tao : Shu Quan = 3 : 5 = 12u : 20u
In 2009, ratio of pupils in Jin Tao : Shu Quan = 4 : 5 = 12u : 15u
So 20u -15u = 120, 5u = 120, 1u = 24

In 2009, number of pupils in Jin Tao = 12u = 12 x 24 = 288

cheers.

Thank you MathIzzzFun :udawoman:

[MathIzzzFun]

Andrew Lee:

MathIzzzFun:

[quote=\"Andrew Lee\"]In 2008, the enrolement of Jing Tao Primary School was 60% that of Shu Quan primary School. In 2009, 120 pupils left Shu Quan Primary School. In the end, the enrolment of Jing Tao Primary School was 80% that of Shu Quan Primary School in 2009. What was the enrolment of Jing Tao Primary School in 2009 ? :idea:

Hi

Number of pupils in Jing Tao remained the same in 2008 and 2009.

In 2008, ratio of pupils in Jin Tao : Shu Quan = 3 : 5 = 12u : 20u
In 2009, ratio of pupils in Jin Tao : Shu Quan = 4 : 5 = 12u : 15u
So 20u -15u = 120, 5u = 120, 1u = 24

In 2009, number of pupils in Jin Tao = 12u = 12 x 24 = 288

cheers.

Thank you MathIzzzFun :udawoman:[/quote]u r welcome

cheers.

[MathIzzzFun]

Andrew Lee:

Hi, Can help me solve this question ?

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Hi

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cheers.

[MathIzzzFun]

Andrew Lee:

Hi, can help me solve this headpain question http://i53.tinypic.com/33lp8jp.jpg\">

Hi

Total 77 cuboids.

First fill up to 8cm in height, this will yield 7 x 2 x 4 = 56 cuboids

The remaining space of 14cm x 6 cm x 3 cm will yield 7 x 3 x 1 = 21 cuboids.

So, total = 56 + 21 = 77 cuboids.

cheers.

[imacsg]

Can anyone help?


Michael bought some apple and gave half of them to Jackson.
Jackson bought some pears and gave half of them to Michael.
Michael threw away 25 pears that were rotten while Jackson bought for himself another 20 apples.
After that, the number of pears to apple Michael had were in the ratio of 1:4 and the number of pears to apples Jackson had were in the ratio of 1:2.
How many pears did Jackson buy?

Ans : 80.

Thanks.

[andante]

Hi


Total 77 cuboids.

First fill up to 8cm in height, this will yield 7 x 2 x 4 = 56 cuboids

The remaining space of 14cm x 6 cm x 3 cm will yield 7 x 3 x 1 = 21 cuboids.

So, total = 56 + 21 = 77 cuboids.

cheers.[/quote]

Sorry to ask how you know that you should fill up to 8cm in height but not to 10cm in height ? Is there any way or trial and error to find out the maximum ?

[MathIzzzFun]

imacsg:

Can anyone help?


Michael bought some apple and gave half of them to Jackson.
Jackson bought some pears and gave half of them to Michael.
Michael threw away 25 pears that were rotten while Jackson bought for himself another 20 apples.
After that, the number of pears to apple Michael had were in the ratio of 1:4 and the number of pears to apples Jackson had were in the ratio of 1:2.
How many pears did Jackson buy?

Ans : 80.

Thanks.

Hi

http://www.flickr.com/photos/62167097@N02/5932660565/in/photostream

cheers.

[MathIzzzFun]

andante:

Hi


Total 77 cuboids.

First fill up to 8cm in height, this will yield 7 x 2 x 4 = 56 cuboids

The remaining space of 14cm x 6 cm x 3 cm will yield 7 x 3 x 1 = 21 cuboids.

So, total = 56 + 21 = 77 cuboids.

cheers.

Sorry to ask how you know that you should fill up to 8cm in height but not to 10cm in height ? Is there any way or trial and error to find out the maximum ?[/quote]

Hi

There is no fixed formula, if that's what you are looking for. In general, try look for two different ways to cut /fill the block:1st way- fill 10 cm, 2nd way-fill 3cm side along the 11cm side, yielding 7 x 3 x 3 cuboids = 63 cuboids and leaving a volume of 14 cm x 6 cm x 2 cm which can yield another 7 x 2 x1 = 14 cuboids making a total of 77 cuboids (this is another way to yield 77 cuboids).

cheers.

[Andrew Lee]

Hi,


When a pebble is dropped into a pool of water, circular ripples are formed 2 consecutive ripples have a radius of 7cm and 14cm respectively. What is the percentage increase in the area of the ripples?

[Andrew Lee]

Hi,


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