Chapter 3 - Section 3-3 - Cumulative Distribution Functions - Exercises - Page 73: 3-48

$F(x)=\left\{\begin{array}{ll}{0,} & {X<1} \\ {0.1,} & {1 \leq X<5} \\ {0.7,} & {5 \leq X<10} \\ {1,} & {X \geq 10}\end{array}\right.$

Since, $f(x)=\left\{\begin{array}{ll} {0.1,} & {X=1} \\ {0.6,} & {X=5} \\ {0.3,} & {X = 10}\end{array}\right.$ then, $F(x)=\left\{\begin{array}{ll}{0,} & {X<1} \\ {0.1,} & {1 \leq X<5} \\ {0.1+0.6=0.7,} & {5 \leq X<10} \\ {1,} & {X \geq 10}\end{array}\right.$