Tutor MathsGuru: Ask me for your burning Maths questions!

[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,


http://i53.tinypic.com/4kfmsy.jpg\">

[leeven]

anybody can post 2011 NMOS special round Question & Answers

[K mum]

Please help me to solve these problem sum:


1.Ali has six times as many marble as Norman. The ratio of the number of Norman’s marbles to the number of Ray’s marbles is 5: 3. Find the ratio of the number of Ali’s marbles to the number of Ray’s marbles.

2. A box contained some green pens and blue pens in the ration 7 : 2. After removing 22 green pens and putting in 18 blue pens, there is now an equal number of green and blue pens in the box. How many green pens were in the box at first ?

3.The ratio of the number of soccer balls to that of basketballs in a storeroom was 2 : 3. When another 144 balls were put into the storeroom, there were twice as many soccer balls and thrice as many basketballs. How many soccer balls & basketballs were there in the storeroom originally ?

[cherylim23]

1. Ali:Norman=6:1=30:5

Norman:Ray=5:3
Ali:Norman:Ray=30:5:3

2. This is how I solved it when I was P5 O.o
Let the number of blue pens be 2x.
solve(2x + 18 = 7x - 22, x)
x= 8
Hence, 56 green pens

3. Let number of soccer balls originally be x.
solve(2x + 3x + 144 = 4x + 9x, x)
x=18
There were 18 x 2 soccer balls and 18 x 3 bballs originally

I hope I’m actually helping you and not harming you.

[K mum]

Hi Maths Guru,

Please help me to solve these problem :

1.\tRyan, Shaun and Raymond decided to pool some money to buy a present. Ryan agreed to contribute 30% of the cost of the present while Shaun agreed to pay 40% of the remaining amount. The remaining cost of the present will be paid by Raymond. However, when the 3 of them when to the shop, the price of the item had increased due to the inclusion of 7% GST. As a result, Ryan paid $64.20 for his share.
a)\tWhat was the price of the present before GST ?
b)\tHow much did Raymond pay for the present including GST



2.\tMr. Tan had some oranges for sale. The first customer bought ½ of the oranges and received 8 oranges free. The second customer bought 45% of the remaining oranges and received 5 oranges free. The third customer bought 70% of the remaining oranges and received 3 oranges free. Mr. Tan then had 1 dozen oranges left. How many oranges did he have at first ?

3. In a Mathematic quiz, pupils who answered each question correctly will be awarded some points according to the topic related as shown in the table below :
Topics\t Points Awarded
Fractions\t3 points
Geometry\t4 points
Volume\t 5 points
Percentage\t6 points

The number of question on Fraction, Geometry, Volume and Percentage were in the ration 5 : 4 : 3 : 2 respectively. Weiling answered all the quiz questions on Fractions and Geometry correctly, but she had got only 1/3 of the question on Volume correct and scored 0 for question on Percentage. If Weiling scored 108 points for here quiz,
a)\tHow many questions on Percentage were there in the quiz?
b)\tHow many questions were there in the quiz?


Thank you.

[K mum]

Hi,


Pls help me to solve the problem sums for P5 ratio :

1.Ali has six times as many marble as Norman. The ratio of the number of Norman’s marbles to the number of Ray’s marbles is 5: 3. Find the ratio of the number of Ali’s marbles to the number of Ray’s marbles.


2. The ratio of the number of soccer balls to that of basketballs in a storeroom was 2 : 3. When another 144 balls were put into the storeroom, there were twice as many soccer balls and thrice as many basketballs. How many soccer balls & basketballs were there in the storeroom originally ?

Thank you very much!