Refer to the diagram shown below.
The distance between the two rocks is (a + b).
By definition,
tan(28°) = 11/a
a = 11/tan(28°) = 20.688 ft
Similarly,
b = 11/tan(19°) = 31.9463 ft
The distance between the rocks is
20.688 + 31.9463 = 52.6343 ft
53 ft (nearest foot)