Answer:
38:81
Explanation:
There are a total of 81 Astronauts in the space program.
Out of these, 43 are in outer space.
We are to determine the ratio of the number of astronauts on Earth to the total number of astronauts.
Number of Astronauts on Earth = Total Number - Number in Outer Space
=81-43 = 38
Therefore:
Number of astronauts on Earth : The total number of astronauts. = 38:81