What number am i?! please help!?

Question

my number is the product of three different prime numbers

it is an odd number less than 125

the sum of its digits is a multiple of 3

one of its factors is the third prime number

please explain????????!!!!!!!

what is the number?

Answer 1

the 3rd prime number is 5.

if the sum of its digit is a multiple of 3 => the number we are looking for is divisible by 3.

since its the product of 3 different prime numbers, we have to find the 3rd prime number. the result is an odd number, less than 125.

the next prime number after 5 is 7.

lets check if the resulting product is less than 125.

3*5*7 = 15*7 = 105 <125.

so there's your answer: 105= 3*5*7.  

Answer 2

1) If one of its factors is the third prime number, then we know that 5 is this number.

2) If the sum of it's digits is a multiple of three, we know it is divisible by 3 (which is also a prime number) and thus we have another of its factors.

3) 3 times 5 = 15. 125/15 = 8.33.

4) Since the number is less than 125, the last factor is 8 or less. Since all the factors are prime numbers, then it can not be 8 or 6 or 4.

Since it is an odd number, the factor can not be 2.

5) This leaves 7

7 * 5 * 3 = 105

Answer 3

prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, etc

the third prime number is 5

the sum of its digits is a multiple of 3, so the number is a multiple of 3

5 and 3 are two of the factors

15*2 =30 not odd

15 * 7 = 105 is the answer

Answer 4

105

There might be better ways to solve this, but I took the primes starting with 2,3,5,7,11.

11(5)(2) is even and 11(5)(3) > 125, so, 11 is out

any number times 2 is going to be even, so 2 is out.

that leaves 3,5,7 = 105

Answer 5

If the sum of the digits is a multiple of 3, the number is a multiple of 3.

The third prime is 5.

The number is odd

So, it has to be 15 or 45 or 75 or 105.

105 is the only product of three DIFFERENT primes (3x5x7)

Answer 6

It either ends in a five or zero because the third prime number is five. All numbers divisible by five either have a five or zero.

The sum of the digits must be a multiple of three. That means that if you had all three digits together, you will either get a 3, 6, 9, 12, etc.

It is an odd number, and since it already has to end in a five or zero, now it can only end in a five because zero is an even number.

Now just try some numbers ending in five.

115 - NO; sum of digits isn't divisible by three

105 - POSSIBLE

95 - NO; sum of digits isn't divisible by three

85 - NO; sum of digits isn't divisible by three

75 - POSSIBLE

65 - NO; sum of digits isn't divisible by three

55 - NO; sum of digits isn't divisible by three

45 - POSSIBLE

35 - NO; sum of digits isn't divisible by three

25 - NO; sum of digits isn't divisible by three

15 - NO; sum of digits isn't divisible by three

105 is the only one answer that can be derived by multiplying three different prime numbers 3 x 5 x 7.

Answer 7

the third prime number is five, as 2, 3, then 5 have no factors other than themselves and one, so it must end in a 0 or 5