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:
21 comments Page 3 of 3.
Dhanush said:
3 weeks ago
Two consecutive no : x, x+2.
Sum of two consecutive no = ?
Diff of squares of 2 consecutive no = 84.
(x+2)^2 -x^2 = 84.
( x^2 + 4 + 2(2x)) - x^2 = 84,
(x^2 +4 + 4x) - x^2 = 84,
x^2 - x^2 + 4 + 4x = 84,
4x = 84 - 4,
x = 80/4,
x = 20.
Sum of two consecutive no = x + (x+2).
20 + (20 + 2) = 42.
Sum of two consecutive no = ?
Diff of squares of 2 consecutive no = 84.
(x+2)^2 -x^2 = 84.
( x^2 + 4 + 2(2x)) - x^2 = 84,
(x^2 +4 + 4x) - x^2 = 84,
x^2 - x^2 + 4 + 4x = 84,
4x = 84 - 4,
x = 80/4,
x = 20.
Sum of two consecutive no = x + (x+2).
20 + (20 + 2) = 42.
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