Q&A - P5 Math

[MathIzzzFun]

I post this the second time.Please help me.

cheers.

[fire_fly]

Cd you plus help....
From Red swastika sa12013:
The ratio of the age of Mdm Huda to her son's age is 5:1 now. In 7 years time, she would be thrice as old as her son. What is the total age of Mdm Huda and her son now?
Thank you. ...

[homeworkgurusg]

Cd you plus help....
From Red swastika sa12013:
The ratio of the age of Mdm Huda to her son's age is 5:1 now. In 7 years time, she would be thrice as old as her son. What is the total age of Mdm Huda and her son now?
Thank you. ...

Before ratio --> H : S = 5 : 1 (difference 4u)
After ratio --> H : S = 3 : 1 (difference 2u)
Age difference between Mdm Huda and her son is unchanged after 7 years

So make the difference same
After ratio (x2) --> H : S = 6 : 2 (difference 4u now, same as before)
1u (6u-5u) --> 7 years
Age of Mdm Huda now is 5u --> 5x7=35
Age of her son now is 1u --> 7

Hope this helps.

Cheers

[Sruthi]

Hi ,

Can you please with the below question ?

Box A and Box B have the same shape and mass.6/7 of Box A and 2/5 of Box B are filled with sand . The mass of Box B with its contents is 7/10 the mass of Box A with its contents. The total mass of the
two boxes with their contents is 680 kg . Find the mass of a empty box .

Thanks.

[Sruthi]

Hi All ,

I am not able to view the problems that are uploaded as image ?
eg. The question posted by belnanna on the area of triangle

Anyone
Thanks.

[speedmaths.com]

Hi ,

Can you please with the below question ?

Box A and Box B have the same shape and mass. 6/7 of Box A and 2/5 of Box B are filled with sand . The mass of Box B with its contents is 7/10 the mass of Box A with its contents. The total mass of the two boxes with their contents is 680 kg .
Find the mass of an empty box .

Thanks.

Hi Sruthi,


Let's try; one possible method:


You may use the "Advanced Model Method" or the "Bags and Boxes" method.


6/7 of Box A and 2/5 of Box B are filled with sand.

30/35 of Box A and 14/35 of Box B are filled with sand.

Box A contains 30 Bags of sand
Box B contains 14 Bags of sand


The mass of Box B with its contents is 7/10 the mass of Box A with its contents.

Ratio of Box A with its contents to B with its contents is 10:7

Ratio of (Box A + 30 Bags) to (Box B + 14 Bags) is 10:7


Cross multiply:

7 Boxes + 210 Bags → 10 Boxes 140 Bags

210 Bags → 3 Boxes 140 Bags

70 Bags → 3 Boxes


The total mass of the two boxes with their contents is 680 kg .

(Box A + 30 Bags) + (Box B + 14 Bags) → 680 kg

2 Boxes + 44 Bags → 680 kg


70 Bags →3 Boxes
1 Bag → 3/70 Box
44 Bags → 44 x (3/70) Boxes


2 Boxes + 44 Bags → 680 kg

2 Boxes + [44 x (3/70) Boxes] → 680 kg

(Can you do this calculation?)

1 Box → 175 kg



Hope this helps

Cheers



speedmaths


PS:
(1)
<<Mod's Note - ad removed : pls comply with our forum's ad posting rules>>

(2)
Some schools use “Bags and Boxes”,
Some schools use the algebraic version of “u” and “p”.
Students may use either version; whichever that they find easier.
.

[leng2005]

Thanks! MathIzzzFun and speedmath.com

[Sruthi]

I did not understand the below Cross multiply portion

Cross multiply:

7 Boxes + 210 Bags → 10 Boxes 140 Bags

210 Bags → 3 Boxes 140 Bags

70 Bags → 3 Boxes

Can you explain the how to do / why we do this step ?

[Daddy]

Have question to ask.

[Sruthi]

can anyone explain if there is any method to find answer for question ?