Let x = how many days Jayden took
Now, since Lana took 1.5 times as long as Jayden, however long Lana took would be 1.5x. We know that Lana took 15 hours, so 15 = 1.5x.
Solving the equation would give us,
x = 15/1.5
so, x = 10
Therefore, Jayden took 10 days.