Understanding the Relationship

* Mass and Fusion Rate: More massive stars fuse hydrogen at a much faster rate. This is because they have stronger gravity, which creates higher pressure and temperature in their core.

* Fuel Consumption: The faster the fusion rate, the faster the star consumes its hydrogen fuel.

Estimating the Difference

While the exact relationship is complex, a good rule of thumb is that the lifetime of a star is inversely proportional to the cube of its mass.

This means:

* A star 10 times more massive will have a lifetime 1000 times shorter (10 cubed).

Applying the Rule

* Our stars have a mass ratio of 15M / 1.5M = 10.

* Therefore, the 15M star will have a lifetime (10)^3 = 1000 times shorter than the 1.5M star.

Answer:

The 1.5M star will fuse hydrogen in its core 1000 times longer than the 15M star.