The fastest crossing of the Atlantic Ocean by an ocean liner was made on July 7, 1952. The ship, the S. S. United States, traveled 4727 km east by northeast in 3 days,
10 hours, and 40 minutes. Assume that the ship had traveled the same speed, but
directly east. What would the velocity of the S. S. United States be in kilometers per
hour?

The speed would be about 80.8 km/h

Explanation:

Notice that the ship really traveled northeast (at 45 degrees north from East) covering eastwards 4727 km.

That means (by using the East projection in a right angle triangle) that the total distance was  (the hypotenuse of the right angle) :

Then the velocity of the ship was the quotient between this distance divided the time it took. Now,notice that the time is given in days, hours, and minutes, but we need the final velocity answer in km per hour. Then we reduce the given time to hours:

3 days + 10 hours + 40 min = 3 (24) h + 10 h + (40/60) h = 248/3 hours which is approximately 82.7 hours.

Then this record speed is the quotient:

6685 km / 82.7 h = 80.8 km/h

it has to be b, about 97 percent.