Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 6)
6.
The sum of the digits of a two-digit number is 15 and the difference between the digits is 3. What is the two-digit number?
Answer: Option
Explanation:
Let the ten's digit be x and unit's digit be y.
Then, x + y = 15 and x - y = 3 or y - x = 3.
Solving x + y = 15 and x - y = 3, we get: x = 9, y = 6.
Solving x + y = 15 and y - x = 3, we get: x = 6, y = 9.
So, the number is either 96 or 69.
Hence, the number cannot be determined.
Discussion:
40 comments Page 2 of 4.
Jayesh said:
9 years ago
x + y = 15.
x - y = 03.
- + - (Changing signs).
----------
2y = 12.
----------
i.e y = 6 (unit place).
Substitute the value of y.
x + y = 15.
So, x + 6=15.
x = 15 - 6.
x =9 (tens place).
Then assume it as 96 and it is the correct one.
x - y = 03.
- + - (Changing signs).
----------
2y = 12.
----------
i.e y = 6 (unit place).
Substitute the value of y.
x + y = 15.
So, x + 6=15.
x = 15 - 6.
x =9 (tens place).
Then assume it as 96 and it is the correct one.
Vicky said:
1 decade ago
I agree with you @Sundar. But if one of the option (69 or 96) is present in option then answer can be determined.
Cannot be determined case exists when both of the options are present and we are unable to decide among them.
Cannot be determined case exists when both of the options are present and we are unable to decide among them.
ROCKY said:
8 years ago
We can't take (10x+y) and (10x-y). Because the question is given that the sum of the digits of a two - digit number.
Exam: a two digit number=98, then sum of the digits 9 and 8=9+8, difference of the digits 9 and 8=9-8.
Exam: a two digit number=98, then sum of the digits 9 and 8=9+8, difference of the digits 9 and 8=9-8.
Anaga said:
7 years ago
(a+b)=(b+a).
(a-b)!=(b-a).
solution:
a+b=15
a-b=3
______
a=9,b=6 i.e ab=96.
b+a=15
b-a=3
______
b=9,a=6 i.e ab=69.
As both the options are correct and present in the solution we cannot determine the correct answer.
(a-b)!=(b-a).
solution:
a+b=15
a-b=3
______
a=9,b=6 i.e ab=96.
b+a=15
b-a=3
______
b=9,a=6 i.e ab=69.
As both the options are correct and present in the solution we cannot determine the correct answer.
Kaveri Malavath said:
5 years ago
If he specified the difference between the first digit and the second digit is 3., then we can determine the answer, which is 96. Since he did not mention anything we can't determine the number.
Sudeshna said:
1 decade ago
If we take the tens digit as 10x then also we will get the value of 10x = 9 and y = 6
So we can easily write the answer as 96 as 9-6 gives 3 and 6-9 gives -3!
So the answer can be determined.
So we can easily write the answer as 96 as 9-6 gives 3 and 6-9 gives -3!
So the answer can be determined.
Mrinu said:
5 years ago
Two digit no are 10x+y.
Let assume x > y.
x + y = 15.
x - y = 3,
x = 9 & y=6.
Number- 10*x+y= 10*9+6 = 96.
if y>x.
10*6 + 9 = 69 .
So, the answer cannot be determined.
Let assume x > y.
x + y = 15.
x - y = 3,
x = 9 & y=6.
Number- 10*x+y= 10*9+6 = 96.
if y>x.
10*6 + 9 = 69 .
So, the answer cannot be determined.
(3)
Moola V reddy said:
1 decade ago
I agree with Dominic
always read the question carefully
1.sum of the two digits
2.difference between them
sundar said good example of difference
but there is no sum
always read the question carefully
1.sum of the two digits
2.difference between them
sundar said good example of difference
but there is no sum
Visalini said:
3 years ago
x+y=15,
x-y=3.
Adding both the equation.so,
2x = 18,
x = 9.
Put x=9 in any equation,
9-y=3,
-y=-5,
Y=5.
The answer is;
X = 9.
Y = 5.
x-y=3.
Adding both the equation.so,
2x = 18,
x = 9.
Put x=9 in any equation,
9-y=3,
-y=-5,
Y=5.
The answer is;
X = 9.
Y = 5.
(1)
Md Jahangir Alam said:
9 years ago
Right answer should be 69. Because when asked about difference we should subtract tenth digit from unit digit. So, answer should be 69.
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