Aptitude - Decimal Fraction - Discussion

Discussion :: Decimal Fraction - General Questions (Q.No.4)

4. 

The value of 0.1 x 0.1 x 0.1 + 0.02 x 0.02 x 0.02 is:
0.2 x 0.2 x 0.2 + 0.04 x 0.04 x 0.04

[A]. 0.0125
[B]. 0.125
[C]. 0.25
[D]. 0.5

Answer: Option B

Explanation:

Given expression = (0.1)3 + (0.02)3 = 1 = 0.125
23 [(0.1)3 + (0.02)3] 8

Acharya said: (Apr 14, 2011)  
How is it explain please.

Sarada said: (Aug 19, 2011)  
How can you common 2^3 from denominator?

Sukeshani Kadam said: (Sep 9, 2011)  
I don't understand this proble. Please explain

Anusha said: (Sep 15, 2011)  
In denominator 0.2 three times multiplied means (0.2)^3 and 0.04 also three times multiplied means (0.04)^3 so from both fractions we taking 2^3 common

[0.2)^3+(0.04)^3]
2^3[(0.1)^3+(0.02)^3

Then numerator and denominator having same value so they canceled each other 2^3 means 8
1/8 =0.125

Vikram Grandhi143 said: (Oct 3, 2012)  
It is just take the common of 0.2 on denominator.

Prasanna said: (Feb 7, 2013)  
It simple guys.

Just divide (0.1) hole power 3 and (0.02) hole power 3 and take cube of 2 so we get the answer 1/8.

Manjula said: (May 24, 2013)  
Hai friends,

They just take 2 common in denominator. (0.2)^3+(0.4)^3 they take 2^3 common. So, 2^3(0.1)^3+(0.2)^3.It is cancelled. 1/8 = 0.125.

Maulik said: (Jan 31, 2014)  
If you calculate with calculator than is the answer is same ?

Can anybody explain it in simple way.

Chandu said: (May 29, 2014)  
First answer is good one we must take the common 2 so we can get the answer essay.

Manuj said: (Sep 12, 2014)  
Can anyone explain the numerator?

Sunilkumar said: (Nov 25, 2014)  
Here,

2*[0.1] = 0.2.
2*[0.02] = 0.04.

Thus taking 2 common.

==> 23 [(0.1)3 + (0.02)3].

Sankar said: (Nov 26, 2014)  
We know the formula, (a^m x b^m) = (ab)^m. In the denominator, take 2^3 common & apply above formula.

Gobi said: (Dec 26, 2014)  
Actual answer is 0.017730666.

Then how is possible 1/8 = 0.0025.

Bangaru Sathish said: (Feb 19, 2015)  
Given problem = [(0.1)^3+(0.02)^3]/[(0.2)^3+(0.04)^3].

Then [(0.1)^3+(0.02)^3]/[(2(0.1))^3+(2(0.02))^3.

Then [(0.1)^3+(0.02)^3]/2^3[(0.1)^3+(0.02)^3].

Then 1/2^3.

Finally 1/8.

Sidharthan M said: (Apr 13, 2016)  
How to convert .008 to 1 and .000064 to 8?

Hema said: (Jul 11, 2016)  
Here

2 * (0.1) = 0.2
2 * (0.02) = 0.04

Then the question we get;

(0.1)^3 + (0.02)^3 / (2(0.1))^3 + (2(0.02))^3.

Then the denominator we can take 2 in common,

(0.1)^3 + (0.02)^3 / 2^3[(0.1)^3 + (0.02)^3].
Then, we can get 1/2^3.
We know 1/8, So we get the answer is 0.125.

Ezra Mike said: (Jul 13, 2016)  
Simple to learn with the given explanations. Thanks.

Chakresh Patel said: (Aug 14, 2016)  
Thanks @Hema.

Jeyendran-Eee said: (Aug 14, 2016)  
We take root of 1/8,

Then we get the answer 0.125.

Vasu said: (Sep 4, 2016)  
2((0.1)^3 + (0.02)^3) = (0.2)^3 + (0.04)^3 why do we have to take 2^3 out of it?

Anupama said: (Feb 23, 2017)  
0.2 = 2/10 = 2 * (0.1).
And 0.04 = 4/100 = 2(2/100) = 2 * (0.02).

Taking 2 in common, expression can be written as given explanation.

Saddam said: (Apr 8, 2017)  
(0.1)^3+(0.2)^3=0.9 /(0.2)^3+(0.4)^3 = 0.70,
So, 0.9/0.70 = 0.125.

Shiva Kumar said: (Apr 25, 2017)  
Friends its very simple first remove decimals then you get.

(1^3+2^3/2^3+4^3) = 1+8/8+64 = 9/72 = 1/8.
Dividing you get 0.125.

Sumon said: (Sep 4, 2017)  
Explanation.

0.1^3+0.2^3/0.2^3+0.4^3 look here,
.04^3 means.0.2^3*0.2^3.
So, 0.1/2^3.

Prayag K Babu said: (Feb 17, 2018)  
Hi guys,

We take 2 common in the denominator so that we can cancel the numerator and denominator and post that we are only left with 1/2 and not 1/2^3. Hence the answer is 1/2 that is 0. 5.

If you don't understand just take an example. We have denominator as 8*8*8+4*4*4. So let's take 2 commons, So it will be 2[4*4*4+2*2*2].

Which is nothing but 2[4^3+2^3]. The 2 which we took as common cannot have power 3.

Hope this helps you.

Jyoshna said: (Aug 28, 2018)  
How 1/8=0.125? explain.

Sowmie said: (Dec 1, 2018)  
Just multiply 0.1 * 10 we get 1.
Then 0.2 * 10=2 so 2^3 is 8.
Then 0.04 * 100=4 so 4^3 Is 64.
Then 0.02 * 100=2 so 2^3 is 8.
Now, 1 + 8/8 + 64 = 9/72 = 1/8 = 0.125.

Sahil said: (Dec 14, 2018)  
0.5 can be the answer.

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