Step-by-step explanation: Bruce has 18 goldfish. If Isabelle has 5 times as many goldfish as Bruce she will have 18*5=90 goldfish. If Arlene has 1/3 times as many goldfish as Isabelle she will have 90/3=30 goldfish.
Explanation: We are given that each serving is 3/10 of a pint. To know the number of servings of 1.5 pints, we will simply use cross multiplication as follows: