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:
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 1 of 5.
Siddhesh said:
7 years ago
The product of the given number and sum of digit means;
24 * (2+4) = 144.
So, the answer is 24.
24 * (2+4) = 144.
So, the answer is 24.
(19)
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.
Product × Sum = 144,
In case of 24 => X × 6 = 144,
Hence, X=24.
Therefore 24 is the right answer.
(8)
GAURAV said:
6 years ago
This type of problem doesn't gives a correct answers, as question sentences are itself confusing.
(4)
Sabu said:
7 years ago
11x2 + 13x - 70 = 0.
(x - 2)(11x + 35) = 0.
x = 2.
How does this do?
(x - 2)(11x + 35) = 0.
x = 2.
How does this do?
(3)
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.
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)
Akash said:
9 years ago
The simple method is to check the option.
Options B and C are wrong because of their option B] difference is not 2 and option C] unit digit is greater than 2. So this is neglected.
Now remaining option is 24 checks it 24 * (2 + 4) = 144 is true then it's a right answer.
Options B and C are wrong because of their option B] difference is not 2 and option C] unit digit is greater than 2. So this is neglected.
Now remaining option is 24 checks it 24 * (2 + 4) = 144 is true then it's a right answer.
(2)
Vishnu s said:
6 years ago
@All.
If the 10th place be denoted by 10x then unit place exceeds 2 more than the 10th place then unit place value should be denoted as 10x+2 why they denote x+2 for the unit place. Please explain this.
If the 10th place be denoted by 10x then unit place exceeds 2 more than the 10th place then unit place value should be denoted as 10x+2 why they denote x+2 for the unit place. Please explain this.
(2)
Joel said:
3 years ago
@Ayushi.
=(11x+2)(2x+2)=144 (Multiplication with both values 11x => 2x & 2 and 2 => 2x & 2).
=>22x^2+22x+4x+4 = 144,
22x^2+26x+4-144 = 0,
22x^2+26x-140=0/squaring this value.
11x2 + 13x - 70 = 0.
We get.
(x - 2)(11x + 35) = 0,
x = 2.
=(11x+2)(2x+2)=144 (Multiplication with both values 11x => 2x & 2 and 2 => 2x & 2).
=>22x^2+22x+4x+4 = 144,
22x^2+26x+4-144 = 0,
22x^2+26x-140=0/squaring this value.
11x2 + 13x - 70 = 0.
We get.
(x - 2)(11x + 35) = 0,
x = 2.
(2)
Naresh said:
1 decade ago
Its not the case of confusing..its the case of time consuming...just check the options only two options may give the answer..24 and 46... now apply the second condition given in the problenm to these two options
24*(2+4)=144.. so this is the correct answer
24*(2+4)=144.. so this is the correct answer
(1)
Tejaswi said:
7 years ago
2 digit number can be represented as 10x+y.
Let's take a 2-digit number 52.
it can be written as 50+2.
50=10*5.
So "10 * 5 +2" (10x+y).
Let's take a 2-digit number 52.
it can be written as 50+2.
50=10*5.
So "10 * 5 +2" (10x+y).
(1)
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