Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 5)
5.
A two-digit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is:
Answer: Option
Explanation:
| Let the ten's and unit digit be x and | 8 | respectively. |
| x |
| Then, |  |
10x + | 8 |  |
+ 18 = 10 x | 8 | + x |
| x | x |
10x2 + 8 + 18x = 80 + x2
9x2 + 18x - 72 = 0
x2 + 2x - 8 = 0
(x + 4)(x - 2) = 0
x = 2.
Discussion:
42 comments Page 4 of 5.
Manojit said:
1 decade ago
Product of two digit means multiple of two digit.
Suppose two digit is x, y.
Then x*y=8
y=8/x
Now two digit is x, 8/x.
Then look the above problem.
Suppose two digit is x, y.
Then x*y=8
y=8/x
Now two digit is x, 8/x.
Then look the above problem.
Banty kumar.biet davangere said:
1 decade ago
xy=8,xy+18=yx;
put xy=8 than
8+18=24
so,
xy=24 ans
put xy=8 than
8+18=24
so,
xy=24 ans
Vijay said:
1 decade ago
Find the least value of * for which 7*5462 is divisible by 9?
Please answer the question.
Please answer the question.
Anwar said:
9 years ago
Why we take x and 1/8 explain?
SK.Gopinath Siva said:
1 decade ago
Let me explain the simplest way.
The way is,
Let take two digit no as x and y.
x * y = 8.
xy + 18 = yx.
//xy = 8// .
8+18 = yx.
yx = 24.
The way is,
Let take two digit no as x and y.
x * y = 8.
xy + 18 = yx.
//xy = 8// .
8+18 = yx.
yx = 24.
Priya said:
1 decade ago
Why 18 should be added in the option to get the answer?
Nitika said:
1 decade ago
Above you write 8+18 = 24 but 8+18 is 26 how it is to be 24?
Abc said:
1 decade ago
Only 24 is the product of 8 in this number. So answer is 24.
Krans said:
1 decade ago
Can you said in another way?
Ayesha said:
10 years ago
9x2+18x-72.
How it is simplified further?
How it is simplified further?
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