Assuming that you're talking about a standard deck of 52 cards, there are 4 tens and 4 aces.
So, at the beginning, you have probability 4/52=1/13 to draw a ten.
You replace, and you have an identical probability to draw an ace (you still have 4 favourable cases over 52 total cases).
Multiply the two probabilities to find the answer:
[tex]\dfrac{1}{13}\cdot\dfrac{1}{13}=\dfrac{1}{169}[/tex]
