Need Help for Maths Questions

[Symantec9]

Hi everyone,

 

Another question on Maths, though able to get the answer via 'Guess-&-Check' method, am wondering if there are other methods that shifus here are able to share & highlight.

 

Thank you in advance [Answer provided below]

 

There are some oranges in 3 boxes, A, B and C.

40% of the number of oranges in Box A is equal to 25% of the number of oranges in Box B.

The number of oranges in Box C is 1/3 of the number of oranges in Box B.

 

a) Express the number of oranges in Box C as a fraction of the number of oranges in Box A.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Answer: 8/15]

[Sci10213]

A : B : C

 

Equation (1) -> 2/5 : 1/4 (ie A:B)

Equation (2) -> 1 : 1/3 (ie B:C)

 

make B = 1 unit, therefore equation (1) x 4 on LHS & RHS

 

hence A : B => 8/5 : 1

 

Now u get:

 

A : B : C

 

=> 8/5 : 1 : 1/3

 

menas A : C = 8/5 : 1/3

 

therefore to find C/A,

 

(1/3)/(8/5) = 5/24

 

just a guess only...

[Sci10213]

express as A : B : C

 

(1) A : B = 2/5 : 1/4

(2) B :C = 1 : 1/3

 

make B = 1 unit ie multiply (1) on LHS & PHS by 4

 

=> A: B = 8/5 : 1

 

Hence, you get

 

A: B : C = 8/5 : 1 : 1/3

 

to get C/A

 

=> 1/3 / 8/5 = 5/24

[Titanium]

There are some oranges in 3 boxes, A, B and C.

40% of the number of oranges in Box A is equal to 25% of the number of oranges in Box B.

The number of oranges in Box C is 1/3 of the number of oranges in Box B.

 

a) Express the number of oranges in Box C as a fraction of the number of oranges in Box A.

 

40% of Box A = 25% of Box B

2/5 of Box A = 1/4 of Box B

 

Total of box B = 2/5 x 4 = 8/5

 

Box C = 1/3 of Box B

Therefore, 1/3 * 8/5 = 8/15

 

Dunno correct or not...

Edited July 23, 2008 by Titanium

[Ultramega]

just substitute here and there only...

 

C = (1/3)B

(40/100)A = (25/100)B

 

So, B = (25/100)B x (100/40) = (40/25)A

 

Sub, into C = (1/3)B,

 

So, C = (1/3) x (40/25)A = (40/75)A = (8/15)A

[Mivec69]

There are some oranges in 3 boxes, A, B and C.

40% of the number of oranges in Box A is equal to 25% of the number of oranges in Box B.

The number of oranges in Box C is 1/3 of the number of oranges in Box B.

 

a) Express the number of oranges in Box C as a fraction of the number of oranges in Box A.

==============================================================================

 

Ratio A:B is 2/5 : 1/4 -> 8 : 5

 

Ratio C:B is 1:3

Ratio C:A 5:24