Let the least number of six digits which when divided by 4, 6, 10, 15 leaves…
2025
Let the least number of six digits which when divided by 4, 6, 10, 15 leaves in each case same remainder 2 be N. The sum of digits in N is = ?
- A.
3
- B.
5
- C.
4
- D.
6
Attempted by 4 students.
Show answer & explanation
Correct answer: B
To find the sum of the digits of N, the least six-digit number that leaves a remainder of 2 when divided by 4, 6, 10, and 15, we follow these steps:
Step-by-Step Calculation
1. Find the Least Common Multiple (LCM):
First, find the LCM of the divisors 4, 6, 10, and 15.
Prime factorization:
4 = 2^2
6 = 2 * 3
10 = 2 * 5
15 = 3 * 5
LCM = 2^2 * 3 * 5 = 60.
2. Find the smallest six-digit number divisible by the LCM:
The smallest six-digit number is 100,000.
Divide 100,000 by 60: 100,000 / 60 = 1666 with a remainder of 40.
To find the smallest six-digit multiple of 60, add the difference between the LCM and the remainder to the smallest six-digit number:
100,000 + (60 - 40) = 100,020.
3. Add the remainder to satisfy the condition:
The problem states the number must leave a remainder of 2 in each case.
N = 100,020 + 2 = 100,022.
4. Find the sum of the digits of N:
Sum = 1 + 0 + 0 + 0 + 2 + 2 = 5.