Question 975053
The unit digit of a two-digit number is 3<pre>u = 3</pre>and seven times the sum of the digits is the number itself.<pre>7(t+u) = 10t+u

Substitute 3 for u:

7(t+3) = 10t+3
 7t+21 = 10t+3
   -3t = -18
     t = 6</pre>Find the number.<pre>The tens digit is 6 and the units digit is 3, so the number is 63.

Edwin</pre>