Chapter 1 - Introduction to Physics - Problems and Conceptual Exercises - Page 15: 22

$1.6\times10^{-4}~s$

$1.5~million=1.5\times10^{6}$ and $1~s=9,192,631,770~cycles=9.19263177\times10^{9}~cycles$. See page 4. $1.5\times10^{6}~cycles=(1.5\times10^{6}~cycles)(\frac{1~s}{9.19263177\times10^{9}~cycles})=1.6\times10^{-4}~s$