A person measures the depth of a well by measuring the time interval between dropping a stone and receiving the sound of impact with the bottom of the well. The error in his measurement of time is δT=0.01  seconds and he measures the depth of the well to be L=20 meters. Take the acceleration due to gravity g=10 ms–2 and the velocity of sound is 300 ms–1 . Then the fractional error in the measurement, δL/L , is closest to