Answer:
45 horseshoe crabs and 45 sea stars
Step-by-step explanation:
The aquarium initially contained x crabs and x sea stars.
"After 15 horseshoe crabs and 27 sea stars are removed the ratio of horseshoe crabs to sea stars is 5:3"
(x-15):(x-27) = 5:3
(x-15)/(x-27) = 5/3
3(x-15) = 5(x-27)
3x-45 = 5x-135
90 = 2x
x = 45