Answer:
1110
Explanation:
For a number to be a divisible of 15 it has to end in either the digit 5 or the digit 0
It also has to be divisible by both 5 and 3 which are primes
Remember that for a number to be divisible by 3, the sum of the digits must be a multiple of 3. For example 27 is divisible by 3(2+7 9 which is a multiple of 3)
We can ignore 2 digit numbers since we only have one possibility 10
- With these facts lets start with 3 digit numbers and having digits 1 and 0 only, ending in 0, divisible by 3. We get:
100 and 110 are the only possible 3-dgit numbers. Neither is divisible by 3
- Let's go to 4-digit numbers. We get
1000, 1010, 1100, 1110. The only number divisible by 3 is 1110
So the answer is 1110