Answer:
1/8.
Explanation:
Assume the 8 sided die contains the numbers 1 to 8 and the 4 sided die contains the numbers 1 to 4.
There are 8 *4 = 32 combinations of numbers possible when you throw each die once.
There are only 4 ways possible to roll the same number (1-1, 2-2, 3-3 and 4-4).
So the required probability = 4/32 = 1/8.