find the least 5-digit number which on dividing by 4,12,20 and 24 leav...
Problem Statement:
Find the least 5-digit number which on dividing by 4,12,20 and 24 leaves remainder 3 in each case.
Solution:
To find the least 5-digit number which leaves a remainder of 3 when divided by 4, 12, 20, and 24, we need to find the LCM of 4, 12, 20, and 24.
Step 1: Find the LCM of 4, 12, 20, and 24
- The prime factorization of 4 is 2 x 2
- The prime factorization of 12 is 2 x 2 x 3
- The prime factorization of 20 is 2 x 2 x 5
- The prime factorization of 24 is 2 x 2 x 2 x 3
Now, we list the prime factors with the highest power:
Therefore, the LCM of 4, 12, 20, and 24 is 120.
Step 2: Add 3 to the LCM to get the required number
Since the number leaves a remainder of 3 when divided by each of 4, 12, 20, and 24, it means that the number is 3 more than a multiple of each of these numbers.
Therefore, we need to add 3 to the LCM of these numbers to get the required number.
The required number is:
Step 3: Verify that the number satisfies the conditions
We need to verify that the number 123 leaves a remainder of 3 when divided by each of 4, 12, 20, and 24.
- 123 ÷ 4 leaves a remainder of 3
- 123 ÷ 12 leaves a remainder of 3
- 123 ÷ 20 leaves a remainder of 3
- 123 ÷ 24 leaves a remainder of 3
Thus, the required number is 123.