Tutor MathsGuru: Ask me for your burning Maths questions!

[ADoc]

peterch:

Morning....


Please help me with this P5 Math:

The following numbers are the factors of a certain number.

1 , 2 , 3 , __ , 6 , 12 , 18 , __ , 36

a) What is the number?
b) Fill in the missing factors in the 2 boxes above.

Thanks a lot .....

Regards

Hihi...totally understand your concern! This question is ambiguous in the sense that it confuses the student's understanding of factors and the \"normal way\" of completely listing them in ascending order.

The question should be worded as \"....all the factors...\" Strictly going by the position of the blanks (and why is \"9\" excluded by the question), then \"4\" & \"24\" would be possible answers. The \"number\" can be any multiples of 36.

[oscarsem]

good solution

[ozora]

HI try try

thanks for the answer.
I am abit lost at : A: B
Ratio of no of group= 3: 2 . How do you derive=3: 2?

The questions were from my relative's boy's school worksheets. Quite challenging. I am lost in Maths now in using model approach. Think I will have to try out the questions again in order I can help my sons in their Maths next time.

trytry:

LaiHeng:

Need help again
1. Tom had 2 boxes, A and B, containing an equal number of white beads. He divided the white beads in BoxA into groups of 60 and to each group, he added 4 red beads before stringing them up to make necklances.

He divided the white beads in BoxB into groups of 90 and to each group, he added 5 blue beads before stringing them up to make necklances.
When he had finished, there was no more white beads in either boxes and he had used 28 more red beads than blue beads. How many red beads did he use altogther?

BOX-----------------------------..........................--A.......................B
no of white bead in each gp.........................60......................90
Ratio of white beads in each gp....................2........................3
Ratio of no of gp.........................................3........................2
Ratio of additional beads in each box.........3x4=12..............2x5=10
....................................................................6.....................5


Difference of 6units-5units=1unit---------------------28

Number of red beads used=6x28=168

BTW LaiHeng, where did you get the question from?

[trytry]

[quote="LaiHeng"]HI try try

thanks for the answer.
I am abit lost at : A: B
Ratio of no of group= 3: 2 . How do you derive=3: 2?

BOX…A…B
ratio of white beads in 1 gp…2…3

In Box A, every 2 beads in 1 gp.
…every 1bead in 1/2 gp
Similarly, in Box B, every 3 beads in 1 gp
… .every…1 bead in 1/3 gp

No of gp for 1 bead…1/2…1/3
Express as a ratio…1/2x6=3…1/3x6=2
ratio of gp…3…2

[yeonee]

Dharma:

yeonee:

Need Help!


The sum of Ben's age and his younger brother's age is 26. The product of their ages is 144.
What is Ben's age in 20 years' time?

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)?

[ADoc]

yeonee:

Dharma:

[quote=\"yeonee\"]Need Help!


The sum of Ben's age and his younger brother's age is 26. The product of their ages is 144.
What is Ben's age in 20 years' time?

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)?[/quote]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.

[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...

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.


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??



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..

[Emelyn]

Hi all,


Need some help here.

Qn : Jan and Kay had equal number of sweets and equal number of chocolates. Jan ate 12 sweets and Kay ate 18 chocolates and then the ratio of Jan’s sweets to chocolates became 1:7, and the ration of Kay’s sweets to chocolates became 1:4. How many sweets did Jan have at first ?

Many thanks.

[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?

[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: