Question

The table shows the educational attainment of the population of Mars, ages 25 and over, expressed in millions. Find the probability that a randomly selected martian,
aged 25 and over has not completed four years (or more) of college.
Years of High School Years of College
Less than 4 4 only Some (less than 4)
Total
Male
27
Female
19
23
Total
27
51
48
11
16
4 or more
25
25
24
88
82
170
44

Answer 1

Answer:  61/85

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Explanation:

There are 170 million martians surveyed, note the "170" in the bottom right hand corner.

Of this total, there are 48 million who have completed 4 (or more) years of college. Refer to the bottom of the "4 or more" column.

This must mean that 170 - 48 = 122 million martians have not completed 4 or more years of college. This figure of 122 is effectively the sum of nearly everything in the bottom row, except for the 48 and the 170. In other words, 27+51+44 = 122.

We divide the values 122 over 170, and reduce fully, to get the answer we're after.

122/170 = (2*61)/(2*85) = 61/85

This can be thought of as "if we had 85 million people total, then 61 million of them did not complete 4 or more years of college".

Side note: 61/85 = 0.7176 = 71.76% approximately