A four digit number is between 3,000 and 4,000.The sum of its digits is 21.The product of the thousand and ones digits 24.The hundreds digit.What is the number?

3 answers

So...
Your number is between 3000 and 4000
The sum of its digits is 21.
The product of the thousand and ones digits 24.
What about the hundreds digit?
Consider the number to be ABCD
We know that A = 3
so 3+B+C+D = 21
B+C+D = 17
"The product of the thousand and ones digits 24" ==== 3*D = 24
D = 8
That leaves B+C = 9

Once you have decided what the story is with the hundreds digit,
you will be able to finish it

so far we have:
3BC8 , where B+C = 9