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Question Write a 6-digit number that is divisible by 15, such that when the digits are reversed, it is divisible by 6.
We know that if the number is divisible by 3 and 5, then it is also divisible by 15. Consider the number 643215. Sum of the digits = 6 + 4 + 3 + 2 + 1 + 5 = 21, which is divisible by 3. Thus, 643215 is divisible by 3. One’s place = 5, it is also divisible by 5. Hence, 643215 is divisible by 15. One’s place is not 0, because the digits are reversed, it becomes a 5-digit number. Lakhs place is always taken as an even number. Reversed the digits: 512346 One’s place = 6, 512346 is divisible by 2. Sum of the digits = 5 + 1 + 2 + 3 + 4 + 6 = 21. It is also divisible by 3. Hence, 512346 is divisible by 6.