This is a poorly defined question. Assumptions must be made to answer it. The answer depends upon how the shaded areas are arranged relative to the statistical distribution (centroid and standard deviation) of dart throws.
They probably expect you to assume that the distribution or dart locations is uniform over a collection of equal-area triangles, with no darts falling outside. This is a highly unlikely situation.
In that case, 1/4 of 500 will land in the shaded areas. Take 1/4 of 500.
If you throw 500 darts at a hexagonal shaped dart board, how many will land in the shaded area?
hexagon is divided into 24 triangles. 6 are shaded and 18 are white
2 answers
What percent of the circles are not white 2/5