Direction : Read the following Information carefully and answer the q...
Question: What is the digit in the tens place of Rahul's roll number in LES Exam?
Given Information:
- Rahul's roll number is a number consisting of three non-zero distinct digits.
- The sum of the digits at hundreds and unit’s place is equal to that half of the digit at ten’s place.
- The sum of all possible three digit numbers obtained using these three digits without repetition is 2664.
Solution:
Let's assume the digits in Rahul's roll number are a, b, and c. Then, we can write the following equations based on the given information:
- a, b, and c are three non-zero distinct digits.
- a + b = c/2
- The sum of all possible three digit numbers obtained using these three digits without repetition is 2664.
Using the third equation, we can find the sum of all possible combinations of a, b, and c:
(a + b + c) + (a + c + b) + (b + a + c) + (b + c + a) + (c + a + b) + (c + b + a) = 2664
Simplifying the equation, we get:
2(a + b + c) = 2664
a + b + c = 1332
Now, we can substitute the second equation in terms of c in the third equation:
a + b + (2a + 2b) = 1332
3a + 3b = 1332
a + b = 444
We can solve these equations to find the values of a, b, and c:
a + b = 444
a + b = c/2
c = 2(a + b)
Substituting the value of c in terms of a and b:
2(a + b) = 2a + 2b + c
c = 2(a + b) - 2a - 2b
c = 2(b - a)
As c is a non-zero digit, b must be greater than a. The possible values of (a, b) are:
(1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (1, 8), (2, 3), (2, 4), (2, 5), (2, 6), (2, 7), (2, 8), (3, 4), (3, 5), (3, 6), (3, 7), (3, 8), (4, 5), (4, 6), (4, 7), (4, 8), (5, 6), (5, 7), (5, 8), (6, 7), (6, 8), (7, 8)
We can find the corresponding values of c for each pair of (a, b):
c = 2(b - a)
Adding all the possible values of c, we get:
2 + 4 + 6 + 8 + 10 + 12 + 14 + 4 + 6 + 8 + 10 + 12 + 14 + 6 + 8 +