SOLUTION: In a three digit no, the difference between the hundreds digit and its tens digit is equal to the difference between its tens digit and its units digit.Also the sum of the digits i

Question 146473: In a three digit no, the difference between the hundreds digit and its tens digit is equal to the difference between its tens digit and its units digit.Also the sum of the digits is 9. How many nos r possible which satisfies the above conditions..?
(1)6 (2)7 (3)8 {4}9
Ans i opted is 6....but given no is 9...could anyone pplz explain...??
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
You're looking for a number ABC.
You know that A can vary from (0,9).
You know that B can vary from (0,9).
You know that B can vary from (0,9).
You know that
1.
because the difference between the hundreds digit and its tens digit is equal to the difference between its tens digit and its units digit.
You also know that
2.
because the sum of the digits is 9.
If we re-arrange eq. 1, you get,
1.
1.
If we re-arrange eq. 2, you get,
2.

Since the two right hand sides are equal they are equal to each other.

Now you have the middle number.
Using eq. 1, you get
A is either greater than 3 or less than 3 from B.
So it can either be 6 or 0.
C is also either greater than 3 or less than 3 from B.
So it can either be 0 or 6.
ABC is then either 630 or 036.
Usually 036 does not count as a 3 digit number.
ABC=630.
I'm not sure what the 1,2,3,4 choice are. Is that the first number.
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