The ratio of the number of astronauts on Earth to the total number of astronauts is 20 : 21 or approximately 0.9524 when expressed as a decimal.
To find the ratio of the number of astronauts on Earth to the total number of astronauts, add the number of astronauts on Earth to the number of astronauts in outer space, then express the number of astronauts on Earth as a fraction of the total number of astronauts.
Number of astronauts on Earth: 20
Number of astronauts in outer space: 1
Total number of astronauts: 20 + 1 = 21
Now, to find the ratio of the number of astronauts on Earth to the total number of astronauts:

