Find the number of 4-digit numbers greater than 3000 that can be formed from prime numbers from 1 to 10 without repetitions. ( Can't solve by listing out the possible outcomes without calculations )?
1 Answer
May 6, 2018
18
Explanation:
Let's first note that the prime numbers between 1 and 10 is:
2, 3, 5, 7
1 is not prime (see here as to why).
We want 4 digit numbers that are greater than 3000, which means we can't start with the 2. And so there are 3 numbers that can be in the first position (3, 5, 7).
In the following 3 positions, there are 3 numbers to place in there, which can be done
All told then, we have