The object is moving by uniform accelerated motion, so its velocity as a function of time is given by
[tex]v(t)=v_0 + at[/tex]
where [tex]v_0 =2.39 \cdot 10^4 m/s[/tex] is the initial velocity of the object, [tex]a=12 m/s^2[/tex] is its acceleration and t is the time.
The object reaches the Sun after a time t=1.5 h, which corresponds to (keeping in mind that 1 h=3600 s)
[tex]t=1.5 h=5400 s[/tex]
So, the velocity of the object when it reaches the Sun is
[tex]v=v_0+at=2.39 \cdot 10^4 m/s + (12 m/s^2)(5400 s)=8.87\cdot 10^4 m/s[/tex]
