Aptitude - Problems on Numbers - Discussion

Discussion Forum : Problems on Numbers - General Questions (Q.No. 9)
9.
In a two-digit, if it is known that its unit's digit exceeds its ten's digit by 2 and that the product of the given number and the sum of its digits is equal to 144, then the number is:
24
26
42
46
Answer: Option
Explanation:

Let the ten's digit be x.

Then, unit's digit = x + 2.

Number = 10x + (x + 2) = 11x + 2.

Sum of digits = x + (x + 2) = 2x + 2.

(11x + 2)(2x + 2) = 144

22x2 + 26x - 140 = 0

11x2 + 13x - 70 = 0

(x - 2)(11x + 35) = 0

x = 2.

Hence, required number = 11x + 2 = 24.

Discussion:
42 comments Page 5 of 5.

Prsd said:   2 years ago
The possibilities are 24 and 46.
Product × Sum = 144,
In case of 24 => X × 6 = 144,
Hence, X=24.
Therefore 24 is the right answer.
(8)

Bradley S said:   1 year ago
@All.

Here, I completely disagree.

The problem indicates in a two-digit if it is known that its unit's digit exceeds its ten's digit by 2. None of the answers presented are for example 31 or 42 , 53 or 64....etc. etc,

The answer of 24, is incorrect within the rule of the question.
(2)


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