I am thinking of a 5 digit number that when tripled is a perfect square.

Also, when the 5 digit number is split, the first number is double the second one. What is the five digit number?

(Splitting the 5 digit number into two numbers means 12345 into 1 and 2345 or 123 and 45.)

We know that the last two digits can range from a low of 50 to a high of 99. Therefore, the first three digits can range from 100 to 198 but exclude all even numbers. Thus the number of combinations that we need to investigate to 50. The solution is 13,467. Clearly, 67 x 2 is equal to 134. Three times 13,467 is 40,401, which is the square of 201.

Gsteel

Posted by Gordon Steel on 2003-08-20 19:09:35