<PRE><B>Question 196261</B>
The tens digit is twice the units digit. The sum of the original number and the number represented when the digits are interchanged is 66.
------------------------------------------------------------------
Let the number be 10t + u ; t is the tens digit ; u is the units digit.
Equations:
t = 2u
10t+u + 10u+t = 66
------------------------
Simplify:
t = 2u
11t + 11u = 66
------------------------
Simplify:
t = 2u 
t + u = 6
--------------------------------
Substitute:
2u + u = 6
3u = 6
u = 2 (units digit)
---
substitute into t = 2u to get:
t = 2u = 2*2 = 4 (tens digit)
--------------------------------
Original Number:
10t + u = 42
=======================
Cheers,
Stan H.

</PRE>