Cecilia watched 1 2 of a movie in the morning, and she watched some more at night. By the end of the day, she still had 1 3 of the movie left to watch. How much of the movie did Cecilia watch at night?

1/6 of the movie.

Step-by-step explanation:

First, she watches 1/2 of the movie.

This means that if the movie lasts N minutes, the time left is:

N - (1/2)*N = (1/2)*N.

Then she watches another part of the movie, let's call it as a*N,  and after that, she has 1/3 of the movie left, we can write this situation as:

(1/2)*N - a*N = (1/3)*N

we can divide by N in both sides to get

(1/2) - a = (1/3)

(1/2) - (1/3) = a

3/6 - 2/6 = a

1/6 = a

So we can conclude that she watched 1/6 of the movie at night.

x=6 and x=3

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