Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 15)
15.
What is the sum of two consecutive even numbers, the difference of whose squares is 84?
Answer: Option
Explanation:
Let the numbers be x and x + 2.
Then, (x + 2)2 - x2 = 84
4x + 4 = 84
4x = 80
x = 20.
The required sum = x + (x + 2) = 2x + 2 = 42.
Discussion:
20 comments Page 2 of 2.
Jack said:
1 decade ago
I think it should be.
(x^2) - (x+1)^2.
(x+x+1)(x-x+1) = 84 //Using a^2 -b^2 formula.
(2x+1)(1) = 84.
2x+1= 84.
2x = 83.
x = 83/2.
(x^2) - (x+1)^2.
(x+x+1)(x-x+1) = 84 //Using a^2 -b^2 formula.
(2x+1)(1) = 84.
2x+1= 84.
2x = 83.
x = 83/2.
Sundar DS said:
8 years ago
(x+2)2/x2 = 84,
x2 + 4 + 4x/x2 = 84,
4x+4 = 84,
4x = 84 - 4,
4x = 80,
x = 20.
The required sum=x + (x+2)
2x + 2,
2 * 20+2 = 42.
x2 + 4 + 4x/x2 = 84,
4x+4 = 84,
4x = 84 - 4,
4x = 80,
x = 20.
The required sum=x + (x+2)
2x + 2,
2 * 20+2 = 42.
(1)
Xayoo said:
4 years ago
x^2 - y^2 = 84,
(x+y)(x-y) = 84,
(42 ) (2) = 84,
(22+20)(22-20) = 84.
x=22 , y = 20.
Therefore x + y = 22+ 20 = 42.
(x+y)(x-y) = 84,
(42 ) (2) = 84,
(22+20)(22-20) = 84.
x=22 , y = 20.
Therefore x + y = 22+ 20 = 42.
Anshu Saini said:
5 years ago
Two consecutive even numbers can only be 2x and 2x+2.
While x and x+2 are example of two consecutive odd numbers.
While x and x+2 are example of two consecutive odd numbers.
(1)
Nivedha said:
1 decade ago
But, if we take x^2-(x+)^2 = 84,
The answer changes to 46.
Can anyone explain why they take (x+2)^2-x^2 = 84.
The answer changes to 46.
Can anyone explain why they take (x+2)^2-x^2 = 84.
Nang said:
8 years ago
Let two consecutive no. Be x, x+2,
Then ,x-x+2=84,
= 84/2,
= 42.
Then ,x-x+2=84,
= 84/2,
= 42.
(2)
Pooja said:
9 years ago
if we took like that (x)^2-(x+2)^2 = 84, answer is changed i.e.46.
Is it correct?
Is it correct?
Abhinayeswari C said:
3 months ago
Very clear explanations. It helps me to understand clearly. Thanks all.
Punam Paswan said:
4 years ago
The consecutive no Be x, x+2,
Then, x-x+2=84,
= 84/2,
= 42.
Then, x-x+2=84,
= 84/2,
= 42.
(6)
Arafath said:
1 decade ago
How does x square become 4x. ?
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