For a Person at Rest,the Velocity V (In Liters Per $v = 0.85 \sin \left( \frac { \pi t } { 3 } \right)$

Multiple Choice

For a person at rest,the velocity v (in liters per second) of airflow during a respiratory cycle (the time from the beginning of one breath to the beginning of the next) is given by​ $v = 0.85 \sin \left( \frac { \pi t } { 3 } \right)$ , ​
Where t is the time (in seconds) .
(Inhalation occurs when v > 0 and exhalation occurs when v < 0. )
​
Find the number of cycles per minute.
​

A) 14 cycles/min
B) 11 cycles/min
C) 10 cycles/min
D) 15 cycles/min
E) 12 cycles/min