The fraction of the reading assignment finished on Monday afternoon is 1/2, and the fraction finished on Tuesday afternoon is 3/10. To find the total fraction finished by Tuesday night, we add these fractions: 1/2 + 3/10.
To add these fractions, we need a common denominator. The least common multiple (LCM) of 2 and 10 is 10. So, we rewrite the fractions with the common denominator of 10:
1/2 = 5/10
3/10 = 3/10
Now we add the fractions:
5/10 + 3/10 = 8/10
Therefore, by Tuesday night, Shane finished 8/10 of the reading assignment.