In a three-digit number, the digit in the unit's place is four times the digit in the hundred's place. If the digit in the unit's place and the ten's places are interchanged, the new number so formed is 18 more than the original number. If the digit in the hundred's place is one third of the digit in the ten's place, then what is 25% of the original number?

Let hundred's place digit = p
Then according to question,
unit's digit = 4 x hundred's place digit = 4p
and Ten's place digit = 3 x hundred's place digit = 3p
So Number = 100 x p + 10 x 3p + 1 x 4p= 134p
If the digit in the unit's place and the ten's places are interchanged according to question,
unit's digit = 3p
and Ten's place digit = 4p
Now Number = 100 x p + 10 x 4p + 1 x 3p = 143p
According to the question, after interchanging,
143p - 134p = 18
⇒ 9p = 18
∴ p = 2
Original number = 134p = 134 x 2 = 268
25% of original number = 268 x 25/100 = 67