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[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.

[Daddy]

Thanks iFruit & Tang. Sorry, but I do not understand the solutions from iFruit & Tang.

Any model to show? Thanks…

Daddy

[kancheongmum]

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.

Hi Daddy

5/5 ---- 30 dolls
1/5 is 1u

(box)()()()
(box)()()()()()

2u --- 0.84 kg
1u --- 0.42 kg
5u --- 30 dolls --- 0.42kg x 5u ---- 2.1kg

1 doll --- (2.1)/30 ---- 0.07kg

Doll ()()()()
-Box()()()()()

(Please note that this unit is different from the unit we workout for box and doll. In the question it said doll is 4/5 of box)

4u ---- 0.07kg
weight of box --- (0.07/4) x 5 ----- 0.0875 kg


Total mass of 1 doll and the box --- 0.07kg + 0.0875kg ---- 0.1575kg

[Tang]

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).



[B][][][]
[B][][][][][]

2 U --> 0.84 kg

1U --> 0.84/2 = 0.42 kg

30 dolls --> 5 x 0.42 = 2.1 kg

1 doll --> 2.1/30 = 0.07 kg

Box --> 5/4 x 0.07 = 0.0875 kg

Box + 1 doll --> 0.0875 + 0.07 = 0.1575 kg

or

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.

Hi,

Model drawing is in dark blue.

[Daddy]

Thanks to all,


Hi Tang,

I do not understand this statement in bold.

Box --> 5/4 x 0.07 = 0.0875 kg
Box + 1 doll --> 0.0875 + 0.07 = 0.1575 kg.

[Tang]

Daddy:

Thanks to all,


Hi Tang,

I do not understand this statement in bold.

Box --> 5/4 x 0.07 = 0.0875 kg
Box + 1 doll --> 0.0875 + 0.07 = 0.1575 kg.

Hi,

Given question:

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).


The mass of each doll is 4/5 times the mass of the box. -- So the mass of the box is 5/4 times the mass of each doll.

[Vanilla Cake]

clblinym:

Dear Parents,

please help me solve the following Math question for my DS.
I have no idea how to solve and the answer was not given.
Thanks in advance.
Regards,
Amy
http://www.postimage.org/image.php?v=aV2Ofii

This question was from Singapore Mathematical Olympiad for Primary Schools 2004 - Q26.