An object travels along horizontal straight path at a constant rate. the object travels 1/20 of the length of the pathing 3/4 seconds. at that rate, how many seconds does it taketh object to travel the entire path

The answer is 15 seconds .

1/20 is a tiny portion of the length that needs to be traveled.  20/20 is the whole length.  If 1/20 gets traveled in 3/4 of a second, multiply 3/4 by 20 to see how long it takes to travel 20(1/20) which is equal to 1, the whole path.
20(3/4) = 15 seconds