Tutor MathsGuru: Ask me for your burning Maths questions!

[kancheongmum]

Smosh:

Hi!


Anne has $165 and Cally had $200 at first.
After spending an equal amount of money, Cally had twice as much money as Anne. How much money did each of them spend?

I was able to solve it by algebra, but my son in P4 cant use it.
Anyone able to help me with the correct method of solving?

Thanks so much in advance

Hi Smosh

This type of question is unchanged difference. Just like you solve age problems. You see, Anne and Cally spent the same amount of money. So the difference in the amount they have before and after is the same. With that you can work out the solution without algebra.

Rdgs

[kancheongmum]

Muffins:

oh! i meant to write that x equals units. will amend my post....

Hi Muffins


I my opinion if you write x equals units, it still not clear. In this particular question x is the no. of pupils.

Rdgs

[Modelmatics]

Smosh:

Hi!


Anne has $165 and Cally had $200 at first.
After spending an equal amount of money, Cally had twice as much money as Anne. How much money did each of them spend?

I was able to solve it by algebra, but my son in P4 cant use it.
Anyone able to help me with the correct method of solving?

Thanks so much in advance

Hi Smosh,

You can also teach your kid using the Model Method.

Step 1: This question involves the <a href=\"http://www.teach-kids-math-by-model-method.com/constant-difference-concept.html%22%3EConstant Difference Concept</a>, i.e., the difference between the 2 variables remains a constant before and after the transfer (the spending of an equal amount of money). It would be easier to work backwards starting with the \"After\" model and work back to the \"Before\" model. We first draw 2 boxes to represent the amount of money Cally had and 1 box to represent the amount of money that Anne had.

http://postimage.org/image/1xq3kz9z8/

Step 2: Next, we draw a box each to the left of both Cally's and Anne's model to show the equal amount of money both had spent.

http://postimage.org/image/1xr3yswuc/

Step 3: Then we label the amount of money that Anne had before the spending as $165 and the amount of money that Cally had before the spending as $200.

http://postimage.org/image/1i6qeln38/

Step 4: From the model, we can see that the difference between Anne and Cally's money is equivalent to 1 unknown unit (represented by \"?\").

http://postimage.org/image/1i6tpoc2s/

Thus,

1 unit ----------> $200 - $165 = $35

Putting the value of 1 unit = $35 back into Anne's model,

$165 - $35 = $130

Therefore, both of them spent $130.

[Daddy]

Hi,


I have questions to ask. Thanks.

1. The ratio of the no. of adults to the no. of children was 4:3. The ratio of the no. of men to the no. of women was 3:5.
a) What was the ratio of the no. of women to the no. of children?
b) There were 180 men at the party. how many people were there at the party?

:?
Thanksss.
Daddy

[Tang]

1. The ratio of the no. of adults to the no. of children was 4:3. The ratio of the no. of men to the no. of women was 3:5.

a) What was the ratio of the no. of women to the no. of children?
b) There were 180 men at the party. how many people were there at the party?



M : W = 3 : 5, so A = 3 + 5 = 8

A : C = 4 : 3 = 8 : 6 (x 2)

W : C = 5 : 6

a) The ratio of the no. of women to the no. of children was 5 : 6.


8 + 6 = 14

3 u –> 180

14 u –> 180/3 x 14 = 840

b) There were 840 people.

[Tang]

Anne has $165 and Cally had $200 at first.

After spending an equal amount of money, Cally had twice as much money as Anne. How much money did each of them spend?



2 - 1 = 1

1 u –> 200 - 165 = $35

165 - 35 = $130

or 200 - 35 - 35 = $130

Each of them spent $130.

[Daddy]

Thanks Tang..

[Daddy]

Hi,


I have questions to ask. Thanks.

1. A box contains 30 similar dolls. The total mass of the box with 3/5 of its contents is 0.84Kg lighter than the box with all its contents. The mass of each doll is 4/5 times the mass of the box. Find the total mass of the box and a doll. ( Give your answer in Kilograms).

Thanks
Daddy.

[iFruit]

Daddy:

Hi,


I have questions to ask. Thanks.

1. A box contains 30 similar dolls. The total mass of the box with 3/5 of its contents is 0.84Kg lighter than the box with all its contents. The mass of each doll is 4/5 times the mass of the box. Find the total mass of the box and a doll. ( Give your answer in Kilograms).

Thanks
Daddy.

2/5 of 30 dolls = 12
mass of 2/5 of 30 dolls = 0.84kg

mass of each doll = 0.07kg

Mass of box = 5/4x 0.07 kg

Mass of Box + doll = 0.07 (5/4 + 1) = 0.07 x 9/4 = 0.63/4 = 0.1575kg

HTH

[Tang]

1. A box contains 30 similar dolls. The total mass of the box with 3/5 of its contents is 0.84Kg lighter than the box with all its contents. The mass of each doll is 4/5 times the mass of the box. Find the total mass of the box and a doll. ( Give your answer in Kilograms).



1 D – 4 u
1 B – 5 u

30 x 4 = 120

3/5 x 120 = 72

5 u + 120 u –> 5 u + 72 u + 0.84 kg

48 u –> 0.84 kg

9 u –> 9/48 x 0.84 = 0.1575

The total mass of the box and a doll was 0.1575 kg.