An airline passenger feel asleep halfway to her destination. When she awoke, the distance remaining was half the distance traveled while she slept. How much of the entire trip was she asleep?

Answer 1

Forget the halfway for a minute.

From the point she fell asleep, she slept twice as long as the rest of the flight after waking. Does that smell like 2/3 + 1/3 to you?

Back to the halfway bit...

She slept 2/3 of the second half of the flight.

She slept 2/3 of half of the flight.

She slept 2/3 * 1/2 of the flight.