Question

Samuel was riding in the back seat of the station wagon on the way home after a long and tiring day at the

beach. He fell asleep halfway home. He didn't wake up until he still had half as far to go as he had already
gone while asleep. How much of the entire trip home was Samuel asleep?

Answer 1

Answer: One fourth of the entire trip.

Explanation:

The initial distance is D.

" He fell asleep halfway home."

Then he fells asleep when the distance between his actual position and his house was half of D, or:

D/2.

"He didn't wake up until he still had half as far to go as he had already

gone while asleep."

So he wakes up when his actual position is a fourth of the initial distance:

(D/2)/2 = D/4.

Then if the entire trip has a distance D, and he was sleeping between:

D/2 - D/4 = 2D/4 - D/4 = D/4.

in a trip of a distance D, he was asleep a distance of D/4.

Then, returning to the question:

How much of the entire trip home was Samuel asleep?

This is equal to the quotient between the distance that he travels asleep and the total distance:

r = (D/4)/D = 1/4.

Then he was asleep in 1/4 of the entire trip.