Answer
Since maximum density of the curve is 5, there are no values above 5. Hence:
$P(4 < Y \leq 5) = 1/5 = 0.2$
Work Step by Step
Since maximum density of the curve is 5, there are no values above 5. Hence:
$P(4 < Y \leq 5) = 1/5 = 0.2$