there were 149 angelfish and goldfish in an aquarium. there were twice as many guppies as angelfish. after selling 35 goldfish there are half as many goldfish as angelfish. how many fish are left in the aquarium

Answer 1

Guppies=2*angels
angels+goldfish=149
goldfish-35=1/2 angels

three equations,three unknowns. I would start with the last two equations, subtract the latter from the second, getting
angles+35=149-1/2 angels
1.5 angels=114
angels=228/3=79
you take if from there...