Tutor MathsGuru: Ask me for your burning Maths questions!

[david59]

pineapple tarts:

Dear Mathsguru,


Aiyoh, I thot I am very clever with such questions already. Sikali I got stuck with this one. Pls help me.

There are 50 and pen and pencil. Each pen cost $6 and each pencil cost $5. The total cost is $47 MORE THAN the total cost of the pencil. How many pen and how many pencil are there?

May I first say that this sentence ' total cost is $47 more than the total cost of the pencil' gives the impression that the total cost of all the pens and pencils is $47 more than . . .I believe you are saying that the total cost of the pens is $47 more than the total cost of the pencils.

OK. I would usually start by using smart guessing of 25 pens and 25 pencils. That is : 25 pens cost $150 and 25 pencils cost $125. The difference btw the two is $25.
Now, if I change 1 pencil to 1 pen, I would be effectively minusing $5 from the total cost of pencils but adding $6 to the total cost of pens. Thus the difference would increase by $11.
So, 2 pencils change to 2 pens is $22.
$25 + $22 = $47
Therefore 27 pens cost $162 and 23 pencils cost $115. The difference is $47.

[YLH88]

Hi Mathsguru,


Need your help with the below question :

In a lecture hall, there were 2 classes of students seated inside, and the ratio of the number of boys to the number of girls was 5 : 6
40% of the boys and 37.5% of the girls in the hall belonged to Class A.
Given that Class A had 21 more girls than boys, how many more students did Class B have than Class A ?


Thank you so much!

[CoffeeCat]

YLH88:

Hi Mathsguru,


Need your help with the below question :

In a lecture hall, there were 2 classes of students seated inside, and the ratio of the number of boys to the number of girls was 5 : 6
40% of the boys and 37.5% of the girls in the hall belonged to Class A.
Given that Class A had 21 more girls than boys, how many more students did Class B have than Class A ?


Thank you so much!

40% = 2/5
Let the number of boys be 5 units and girls 6 units.
students in hall that are boys from A : 40% * 5 units = (2/5 * 5 units ) = 2 unit.
students in hall that are girls from A : 37.5% * 6 units = (3/8) * 6 units = 2.25 unit
2.25 unit - 2 unit = 0..25 unit represemts 21 girls
1 unit = 21*4=84
Therefore number of students in A =( 2.25 + 2) *84 = 357
Number of students in class B = (5+6 - 4.25) *84= 567
difference =...

[mathsguru]

pineapple tarts:

Dear Mathsguru,


Aiyoh, I thot I am very clever with such questions already. Sikali I got stuck with this one. Pls help me.

There are 50 and pen and pencil. Each pen cost $6 and each pencil cost $5. The total cost is $47 MORE THAN the total cost of the pencil. How many pen and how many pencil are there?

Hi Pineapple Tarts,

Here's my solution & explanation. Hope can help your child understand...

Cheers,
MathsGuru

http://www.postimage.org/image.php?v=PqwM850

[mathsguru]

pineapple tarts:

Dear Mathsguru,


Another one. I am seeing stars....

There are 100 fruit tarts for 100 people. Each adult had 3 fruit tarts and every 3 children share one fruit tart. How many children are there?

Oh no...poor you...here you go! Hope you don't see stars anymore...


MathsGuru

http://www.postimage.org/image.php?v=PqwMTtJ

[mathsguru]

ttyh:

Pls help me in this...Thanks..

Complete the addition square by finding the missing numbers. (imagine all the numbers inside a 9 grid square)

+ 200 300
50 250 A
60 B 360

A = ?
B = ?

Hi TTYH,

Here's my solution.

Cheers,
MathsGuru

http://www.postimage.org/image.php?v=gxMxFOi

[mathsguru]

YLH88:

In a lecture hall, there were 2 classes of students seated inside, and the ratio of the number of boys to the number of girls was 5 : 6. 40% of the boys and 37.5% of the girls in the hall belonged to Class A.

Given that Class A had 21 more girls than boys, how many more students did Class B have than Class A ?

Hi YLH88,

Here's my solution. You can encourage your child to explore using fraction of a unit in the diagram. In this way, can save time by not re-drawing the diagram in terms of LCM.


MathsGuru

http://www.postimage.org/image.php?v=gxMy6eS

[Dharma]

YLH88:

Hi Mathsguru,


Need your help with the below question :

In a lecture hall, there were 2 classes of students seated inside, and the ratio of the number of boys to the number of girls was 5 : 6
40% of the boys and 37.5% of the girls in the hall belonged to Class A.
Given that Class A had 21 more girls than boys, how many more students did Class B have than Class A ?


Thank you so much!

Boys : 5u = 40u
Girls : 6u = 48u

Boys (Class A) : 4/10 x 40u = 16u
Girls (Class A) : 3/8 X 48u = 18u ... [ 37.5% = 3/8]

2u = 21
1u = 10.5

Boys (Class B) : 40u – 16u = 24u
Girls (Class B) : 48u – 18u = 30u

Additional No. of students in Class B = 54u – 34u = 20u = 20 x 10.5 = 210

[Dharma]

pineapple tarts:

Dear Mathsguru,


Aiyoh, I thot I am very clever with such questions already. Sikali I got stuck with this one. Pls help me.

There are 50 and pen and pencil. Each pen cost $6 and each pencil cost $5. The total cost is $47 MORE THAN the total cost of the pencil. How many pen and how many pencil are there?

There are 50 and pen and pencil. Each pen cost $6 and each pencil cost $5. The total cost of pens is $47 MORE THAN the total cost of the pencil. How many pen and how many pencil are there?

Pens : 1u
Pencil : 1p

Total cost of pens : 1u x $6 = $(6u)
Total cost of pencils : 1p x $5 = $(5p)

Given
1u + 1p = 50 ………….. (1)
$(6u) – $(5p) = $47
6u – 5p = 47 …………….(2)
5u + 5p = 250 …………(3) = (1) x 5
11u = 297 …….[(2) + (3)]
1u = 27 (No. of pens)
1p = 50-27 = 23 (No. of pencils)

[firebird]

Dear Mathsguru


Good evening.

Please help me on the following P6 maths:

1) If Ahmad and Ben work together, they can compete a job in 12 days. If Ahmad and Ben worked together for 3 days, followed by Ben who worked alone for the next 5 days, they can finish 5/12(fraction) of the job. How many days will each of them need to complete the job if they work alone?

2) Allyson, Betty and Charlene shared to buy a watch for their father. Allyson paid 1/4(fraction) of the total share of Betty and Charlene. Betty paid 1/5 (fracion) the total share of Allyson and Charlene. If Charlene paid $56 more than Betty, how much did the watch cost?

Many thanks
firebird