The bald eagle can dive at a speed of 100 miles per hour, while the peregrine falcon can dive at a speed of twice that of the bald eagle.  Starting from the same treetop, if it takes the bald eagle 30 seconds to dive to the ground, how long, in seconds, will it take the peregrine falcon to dive the same distance? Think carefully first, then make a decision:
Twice the speed of the bald eagle is 100 * 2 = 200 miles per hour. Let "x" be the time in seconds it takes the peregrine falcon to travel to the ground. Thus, based on the ratio of their speeds, the following expression is given: x = 30 * (100 / 200). Thus, x = 15 seconds. So, the answer is 15.