Chapter 5 - Continuous Random Variables - Exercises 5.20 - 5.52 - Learning the Mechanics - Page 242: 5.35

$\mu=182$

$p(z\gt z_0)=.9$ $p(z\lt -z_0)=.9$ $p(0\lt z\lt -z_0)=p(z\lt-z_0)-p(z\lt 0)=.9-.5=.4$ If $p(0\lt z\lt -z_0)=.4$ then $-z_0=1.28$ $z_0=-1.28$ $z_0=\frac{x-\mu}{\sigma}$ $-1.28=\frac{150-\mu}{25}$ $150-\mu=-1.28(25)$ $150+32=\mu$ $\mu=182$