Aptitude - Decimal Fraction - Discussion

Discussion Forum : Decimal Fraction - General Questions (Q.No. 3)
3.

The value of (0.96)3 - (0.1)3 is:
(0.96)2 + 0.096 + (0.1)2
0.86
0.95
0.97
1.06
Answer: Option
Explanation:
Given expression
= (0.96)3 - (0.1)3
(0.96)2 + (0.96 x 0.1) + (0.1)2
= a3 - b3
a2 + ab + b2
= (a - b)
= (0.96 - 0.1)
= 0.86
Discussion:
22 comments Page 1 of 3.

Suruthi durai said:   2 years ago
Numerator:a^3-b^3=(a-b)(a^2+ab+b^2).
Denominator:a^2+ab+b^2.
Numerator/denominator = a-b.
= 0.96 - 0.1.
= 0.86.
(5)

Jagga said:   4 years ago
a^3-b^3 = (a-b)(a^2+2ab+b^2).
(2)

Tinkeee said:   7 years ago
No, the correct way to get a^3-b^3 you have to multiply a^2 - ab - b^2 by a-b. We want to get a^3-b^3.

So why are we finding (a^3-b^3) / (a^2+ab+b^2) ? Actual answer is 0.88 not 0.86.
(1)

Haritha said:   8 years ago
a3-b3/a2+ab+b2 = (a3-b3)/(a2+b2)+ab is not equal to a-b.

The denominator will cancel the numerator as both are products of a-b.
ie;it will leave the answer a-b/ab.
(1)

Abhiram said:   8 years ago
We multiply (0.96-0.1) on both numerator and denominator and alike terms are cancelled and we get an answer.

0.96-0.1=0.86.

Sadhuru said:   8 years ago
How to solve ab? Please explain it for me.

Kinyera said:   8 years ago
@ALL.

Just expand (a-b)^3 in the middle somewhere you will get (a^3-b^3), make it the subject.

This must make you understand how a3-b3 = (a-b)(a2+ab+b2) came about.
(1)

Sachin pal said:   9 years ago
As we have formula a3-b3 = (a-b)(a2+ab+b2).

Now,
(a2+ab+b2) is cancel out and we have (a-b)only.
So, .96 -.1 = .86.
(2)

Anandhan said:   9 years ago
But (a + b)3 is = (a - b) (a2 + ab + b2). Here a3 + b3 so how it can be possible? Both are different, Right?

Annie Sethi said:   9 years ago
Given expression
=(0.96)3 - (0.1)3.
(0.96)2 + (0.96 x 0.1) + (0.1)2.

as The formula is

a3 - b3
-----------
(a2 + ab + b2)

So, open this formula of a3 - b3 => (a - b) (a2 + ab + b2)

Then,
(a - b) (a2 + ab + b2)
------------------------------
(a2 + ab + b2)

Cancel the alike terms and yu will get;
= (a - b)
= (0.96 - 0.1)
= 0.86.
(9)


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