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 1 of 5.
Saradhapriyanka.s said:
1 decade ago
I could not understood your answer, please explain in some other way.
Chandra said:
1 decade ago
There are only four two digit numbers whose product of the digits is 8. They are 18, 81, 24 and 42.
We can get easily 24 is the answer.
We can get easily 24 is the answer.
Sun said:
1 decade ago
We can directly check out the answer through options.
24 + 18 = 42 which gives product 8.
24 + 18 = 42 which gives product 8.
Shanthi said:
1 decade ago
It is very simple. You can get answer from the options itself. 18+18=36 no. Not reversed. Tak 24+18=42 no. Reversed. 24 is reversed as 42.
Sudheer said:
1 decade ago
Products of 8 is 2*4, 4*2, 8*1, 1*8.
But he is telling by adding 18 to it the digits are reversed means 24+18=42.
24 is changed to 42. So, the answer is 24.
But he is telling by adding 18 to it the digits are reversed means 24+18=42.
24 is changed to 42. So, the answer is 24.
May said:
1 decade ago
Oh. You great and feeling in so easy. Thanks you.
Sunny said:
1 decade ago
Why didn't you take 8x, 1/x and solve the problem?
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.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers