Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 14)
14.
The sum of two number is 25 and their difference is 13. Find their product.
Answer: Option
Explanation:
Let the numbers be x and y.
Then, x + y = 25 and x - y = 13.
4xy = (x + y)2 - (x- y)2
= (25)2 - (13)2
= (625 - 169)
= 456
xy = 114.
Discussion:
30 comments Page 2 of 3.
Deepakamal said:
1 decade ago
x+y = 25 and
x-y = 13.
To solve this we can get x=19 and y=6.
But the question is product of two no.
So, xy = 19x6 = 114 is the answer
x-y = 13.
To solve this we can get x=19 and y=6.
But the question is product of two no.
So, xy = 19x6 = 114 is the answer
Mahesh said:
1 decade ago
x+y=25.......1.
x-y=13.......2.
Add 1&2
2x = 38,
x = 19 (now substitute x val in 1).
19+y = 25.
y = 6.
x*y = 19*6.
= 114.
x-y=13.......2.
Add 1&2
2x = 38,
x = 19 (now substitute x val in 1).
19+y = 25.
y = 6.
x*y = 19*6.
= 114.
Ganesh said:
8 years ago
Add 25+13=38
Sub. 25-13=12
Then we Wii take the ratio
38:12 which is
19:6
After multiple(19*6=114) these no. We will get 114.
Sub. 25-13=12
Then we Wii take the ratio
38:12 which is
19:6
After multiple(19*6=114) these no. We will get 114.
(4)
Prashanth said:
1 decade ago
x+y=25.......1
x-y=13........2
solving it we get x=19
substituting x=19 in 1st equation
we get y=6
product= xy =19*6=114
x-y=13........2
solving it we get x=19
substituting x=19 in 1st equation
we get y=6
product= xy =19*6=114
JAYESH BRO, said:
1 decade ago
How 4xy?
Ans: Because there two number is 25 & for that's 2+.
(X+Y-X-Y=2xy).
That's why 2+2xy=4xy.
Ans: Because there two number is 25 & for that's 2+.
(X+Y-X-Y=2xy).
That's why 2+2xy=4xy.
Priya said:
9 years ago
Why we are taking x+y and x-y, and another doubt is why we have to take 4xy?
Please clarify this term.
Please clarify this term.
Ezhili said:
2 years ago
4ab = (a+b)^2 - (a-b)^2.
4ab = 25^2 - 13^2.
= 625 - 169.
4ab = 456
ab = 456/4
= 114.
4ab = 25^2 - 13^2.
= 625 - 169.
4ab = 456
ab = 456/4
= 114.
(4)
SHYAM said:
1 decade ago
Find the value of the variable X and Y separately and find the product of both.
Lav said:
9 years ago
x + y = 25.
x - y = 13.
2x = 12.
x = 6.
y = 19.
xy = 114.
x - y = 13.
2x = 12.
x = 6.
y = 19.
xy = 114.
(4)
Smita said:
8 years ago
Please, can anyone explain this in easy way?
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