Tutor MathsGuru: Ask me for your burning Maths questions!

[CJM]

Belle2011:

CJM:

A pond can be filled in 1h by 6 taps following at the same rate. How long will it take for 4 such taps to fill the pond?

1 tap can fill 1/6 pond in an hr.
4 taps can fill 4/6 pond in an hr.
4 taps can fill 2/6 pond in 30 min.
Thus 4 taps can fill 1 pond in 1hr 30 min.

:roll:

thank u so much !

[Idont splat]

err... Can someone pls reply to my questions on page 328 ? :? Sorry if I was too impatient... :oops:

[yeonee]

ADoc:

yeonee:

[quote=\"Dharma\"]
144 = ( 2 x 2 x 2 ) x ( 2 x 3 x 3 ) = 8 x 18
Ben’s age now = 18
Ben’s younger brother’s age = 8
Ben’s age in 20 years’ time = 18 + 20 = 38

Sorry. Could u explain why (2x2x2) x (2x3x3)?

Hi Veonee! Dharma was using a more \"advanced\" concept of factorisation (versus guess & check) in order to find the two numbers that give 26 and 144 when added and multiplied together.

If you were to (prime) factorise 144 into its basic components, you will get
2 x 2 x 2 x 2 x 3 x 3. (start by dividing with 2, proceed to the next (prime) number, 3, when the quotient is no longer divisible by 2)

An alternative (and perhaps more intuitive) for primary students would be to write down all the factors of 144:
1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144
and find two numbers that add and multiply to give 26 and 144.[/quote]
OIC. Thank you very much.

[kwcllf]

yeonee:

ADoc:

[quote=\"yeonee\"]
Sorry. Could u explain why (2x2x2) x (2x3x3)?

Hi Veonee! Dharma was using a more \"advanced\" concept of factorisation (versus guess & check) in order to find the two numbers that give 26 and 144 when added and multiplied together.

If you were to (prime) factorise 144 into its basic components, you will get
2 x 2 x 2 x 2 x 3 x 3. (start by dividing with 2, proceed to the next (prime) number, 3, when the quotient is no longer divisible by 2)

An alternative (and perhaps more intuitive) for primary students would be to write down all the factors of 144:
1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144
and find two numbers that add and multiply to give 26 and 144.

OIC. Thank you very much.[/quote]
Alternatively,

you can break down the sum of their age:

26 = 1 + 25 or 2 + 24 or 3 + 23..........8 + 18


Then you see which combination multiply to give you 144 (which is 8x18)

[Yu Xuan]

Idont splat:

1). Mr Tan brought some pens and pencils to the class.
If he gave away 4 pens and 1 pencils each time, there would be 78 pens left when all the pencils were given away. If 1 pen and 4 pencils were given away each time, there would be 153 pens left when all the pencils were given away. What was the total number of pens and pencils brought by Mr Tan.
..

Hi,

Scenario A
Pen : Pencil
4 : 1
16 : 4

Scenario B
Pen : Pencil
1 : 4

Equate the units of Pencils since it always zero at the end.

16units - 1 unit --> 153 - 78 = 75
1 unit --> 5
Total Pen & Pencil --> (16 + 4) * 5 + 78 = 178

Best wishes in your CA..

[Yu Xuan]

Idont splat:

3).386 children were in the hall watching the show \"Avatat\". Halfway through the show, 2/5 of the boys and 3/4 of the girls walked out, leaving 170 children in the hall. Find the number of boys who walked out from the hall.

Appreciate all your help..& many Thanks..

3] Boys --> 5 units
Girls --> 4 units

5B + 4G ==> 386 *

3B + 1G ==> 170
12B + 4G ==> 680 *

By comparing these two statements *;
7B ==> 680-386 = 294
1B ==> 294 / 7 = 42
2B ==> 42 * 2 = 84

[Muffins]

Idont splat:

Hi Everybody ... Pls help me to solve a few questions...

Been cracking my head but I still cant solve ..Having Maths CA test Tomorrow.. Sobz sobz...

2). Mr Tan had a total of $1741 in two safes. He transferred 5/9 of the money from Safe B to Safe A. Later, he transferred 3/5 of the money from Safe A to Safe B. In the end, he had $601 more in Safe B than
Safe A.
How much money did he have in Safe A then in Safe B at first??
Appreciate all your help..& many Thanks..

What was in A = ($1741-$601)/2 = $1140/2
= $570

What was in B = $1741 - $570 = $1171

570/2 = 285
285 x 5 = 1425
1741 - 1425 = 316
316/4 = 79
79 x 9 = 721
1741 - 721 = 1020

So, in the beginning:

B = 721
A = 1020

[HVR]

deleted

[HVR]

HVR:

There were 258 pupils in the hall. After 1/3 of the boys left and 22 girls entered, the number of boys and girls is equal.

Q1) how many boys were in the hall at first?
Q2) how many more boys than girls were in the hall at first?

Thanks!

Please disregard the above posting. I managed to find the answers. Thanks.

[Muffins]

HVR:

There were 258 pupils in the hall. After 1/3 of the boys left and 22 girls entered, the number of boys and girls is equal.

Q1) how many boys were in the hall at first?
Q2) how many more boys than girls were in the hall at first?

Thanks!

Will try for fun

so, the total numbers of boys and girls will be 2x (since x is for boys, and x for girls, assuming they are equal)

So in the beginning,

Girls = x - 22
Boys = x + 0.5x

so, 2.5x - 22 = 258

2.5x = 280

therefore, x = 112

112 X 1.5 = 168

that's for a, need to go now hope that helped