|
Question 350575: which numberrs are exactly 2 times the sum of their digits
Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website! Hi,
Note: Let td represent a 2 digit number. Then (10*t + d) is the value of the number.
.
Write as You Read
(10*t + d) = 2(t + d)
.
simplifying
10*t + d = 2t + 2d
8*t = d
.
If t =1, then d=8 for example
.
18 is exactly 2 times the sum of its digits
2(1 + 8)= 18
|
|
|
| |
