Aptitude - Decimal Fraction - Discussion

Discussion :: Decimal Fraction - General Questions (Q.No.1)

1. 

Evaluate : (2.39)2 - (1.61)2
2.39 - 1.61

[A]. 2
[B]. 4
[C]. 6
[D]. 8

Answer: Option B

Explanation:

Given Expression = a2 - b2 = (a + b)(a - b) = (a + b) = (2.39 + 1.61) = 4.
a - b (a - b)

Danny Sawkmie said: (Sep 10, 2011)  
Iven Expression = a2 - b2 = (a + b)(a - b) = (a + b) = (2.39 + 1.61) = 4.
a - b (a - b)

Explain clearly

Aptitute said: (Sep 20, 2014)  
Given Expression = a^2 - b^2 = (a + b)(a - b).

(a^2 - b^2)/(a - b) = (a + b) = (2.39 + 1.61) = 4.

Mary Grace said: (Dec 14, 2014)  
Can you explain this clearly? Please.

Praveen Kumar said: (Jun 7, 2015)  
2.39*2.39 = 5.7121.
1.61*1.61 = 2.6565.
2.39-1.61 = 0.78.

Its nothing 5.7121-2.6565/0.78 = 4.

Manas Kumar Patra said: (Jun 23, 2015)  
Can you explain how (a+b)(a-b)/(a-b)=a+b?

Suni said: (Dec 27, 2015)  
(a+b)(a-b)/(a-b), its simple division where a-b gets cancelled an that = a+b.

Franky said: (May 22, 2016)  
This is easy, just (a + b)(a - b)/(a - b).
Then just by cancelling the both minus and remaining a+b is the answer.

Formula : (a^2) - (b^2) = (a + b)(a - b)/a - b.

Enter the amount: (2.39 + 1.61)(2.39 - 1.61)/2.39 - 1.69).
Cancel both 2.39 - 1.61)/(2.39 - 1.69).
Then remaining in the numerator is 2.39 + 1.61 = 4.

So, the answer is 4.

Sabit said: (Sep 8, 2016)  
How did the 2nd step come?

Mahesh said: (Apr 29, 2017)  
Good explanations, Thank you all.

Sindhu said: (May 4, 2017)  
Not getting this. Please Explain me clearly.

Ashwani said: (Mar 18, 2018)  
Here the formula of a2-b2 = (a+b)(a-b).
so (a+b)(a-b)/(a-b) here both (a-b) are canceled,
so (a+b) is reminder here a= 2.39 & b= 1.61,
then 2.39+1.61=4 .

Rajeswari said: (Apr 1, 2018)  
Not getting this, please explain clearly.

Lalita said: (Sep 7, 2018)  
Please explain it again.

Kato Ballack Godfrey said: (Nov 16, 2018)  
Explain how?

Mr.Soumya Dhwaj said: (May 25, 2019)  
See what we have to do is,

(a+b)x(a-b)/(a-b).

(2.39+1.61)x(2.39-1.61) divided by/(2.39-1.61).

Solving them by opening the brackets we get,
4x0.78/0.78.
Now by solving it we get a figure =3.12 divided by/0.78.
Finally, we get = 4 as our answer.

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