5(t+u) = 10t+u
5t+5u = 10t+u
4u = 5t
so, 45 = 5(4+5)
x is a positive integer such that the sum of its digits times 5 equals itself.
What is x??
For example, 32 does not qualify because (3+2)x5=25, not 32.
Prove there is only one possible value for x
2 answers
it is 0
0 answers