Answer
(a) $P(X\lt1.5)=4/7$
(b) $P(X\leq3)=1$
(c) $P(X\gt2)=1/7$
(d) $P(1\lt X\leq2)=2/7$
Work Step by Step
$F(x)=\left\{\begin{array}{ll}{0} & {X<1} \\ {4/7} & {1 \leq X<2} \\ {6/7} & {2 \leq X<3} \\ {1} & {X \geq 3}\end{array}\right.$
$P(X\lt1.5)=F(1.5)=4/7$
$P(X\leq3)=F(3)=1$
$P(X\gt2)=1-F(2)=1-6/7=1/7$
$P(1\lt X\leq2)=F(2)-F(1)=6/7-4/7=2/7$
