Measure of Angles with Parallel Lines

In the figure below, two lines $a$ and $b$ intersect at point $P$. The measure of angle $X$, formed by line $a$, is $40^{ ext{o}}$. If line $c$ is a transversal that intersects lines $a$ and $b$, forming angle $Y$ on line $b$, what is the measure of angle $Y$?

Assume that line $b$ is parallel to line $d$, which intersects line $c$ at another point.