Aptitude - Decimal Fraction - Discussion
Discussion Forum : Decimal Fraction - General Questions (Q.No. 12)
12.
| 4.2 x 4.2 - 1.9 x 1.9 | is equal to: |
| 2.3 x 6.1 |
Answer: Option
Explanation:
| Given Expression = | (a2 - b2) | = | (a2 - b2) | = 1. |
| (a + b)(a - b) | (a2 - b2) |
Discussion:
14 comments Page 1 of 2.
Nitika said:
1 decade ago
Really mind blowing. Very good explanation.
(1)
Akiii said:
1 decade ago
I didn't understand the answer, can you please explain. ?
Divya said:
1 decade ago
Here in numerator 4.2 is expressed as a^2
and 1.9 is expressed as b^2
Similarly it is clearly know from the denominator
Such that (a^2=4.2) and (b^2=1.9)formula for
(a^2-b^2) is (a+b)(a-b)
therefore 4.2+1.9 =6.1 and 4.2-1.9=2.3thus when both are canceled we get 1.0 as result
and 1.9 is expressed as b^2
Similarly it is clearly know from the denominator
Such that (a^2=4.2) and (b^2=1.9)formula for
(a^2-b^2) is (a+b)(a-b)
therefore 4.2+1.9 =6.1 and 4.2-1.9=2.3thus when both are canceled we get 1.0 as result
Suresh said:
1 decade ago
But how you take the numerator as 4.2 = a^2. If it so means a^4-b^4 = 4. 2*4.2 - 1.9*1.9. I can't get your explanation.
Raju trimukhe said:
1 decade ago
Use formula a^2-b^2 = (a+b)(a-b).
(4.2+1.9)(4.2-1.9) = (6.1)(2.3).
Whole expression:
= (6.1)(2.3)/(6.1)(2.3).
= 1.
(4.2+1.9)(4.2-1.9) = (6.1)(2.3).
Whole expression:
= (6.1)(2.3)/(6.1)(2.3).
= 1.
(5)
Prasad said:
1 decade ago
But how to think that much logically?
Harish said:
1 decade ago
Just simply subtract 4.2-1.9 = 6.1 and add 4.2+1.9 = 2.3.
You can easily find logic.
You can easily find logic.
(1)
Arvind_ap said:
1 decade ago
Its simply.
4.1 x 4.1 = 17.64 & 1.9 x 1.9 = 3.61.
Now 17.64 - 3.61 = 14.03.
= 2.3 x 6.1 = 14.03.
So 14.03/14.03.
Answer = 1.
4.1 x 4.1 = 17.64 & 1.9 x 1.9 = 3.61.
Now 17.64 - 3.61 = 14.03.
= 2.3 x 6.1 = 14.03.
So 14.03/14.03.
Answer = 1.
(4)
Shubh said:
7 years ago
Nice & clear explanation. Thanks @Arvind.
Mohan bhuyan said:
5 years ago
Thanks all for explaining the answer.
(1)
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