Marie does three equally time-consuming tasks in a row without taking breaks. She begins the first task at $1:00$ PM and finishes the second task at $2:40$ PM. If she finishes the third task at $x$ PM, express the time $x$ in the format HH:MM PM, where HH and MM are two-digit numbers (possibly with leading zeros), and find the value of HH + MM.

Let's think step by step and output the final answer within \boxed{}.
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