The units digit of a two-digit number is 3 and seven times the sum of the digits is the number itself.
Question:
The units digit of a two-digit number is 3 and seven times the sum of the digits is the number itself. Find the number.
Solution:
Let the tens place digit be x.
The units place digit is 3.
∴ Number = (10x + 3) ... (1)
Given:
7( x + 3) = (10 x + 3)
7 x + 21 = 10 x + 3
∴ 10 x - 7x = 21 - 3
⇒ 3 x = 18
or x = 6
Using x = 6 in equation (1):
The number is 63.