A guitar string that should produce 110 Hz (the note A) instead produces 105 Hz. 

(a) What change in tension is needed to bring the string into tune? 

(b) Sometimes a guitar is tuned to “drop-D” tuning, where the low E string is tuned so that it plays the note D instead. What decrease in tension is needed to bring the string from E (82.4 Hz ) to D (73.4 Hz)? Express your answers as the ratio of the new tension to the old tension, and give your answers to three significant figures.