###Human: There are three goldfish and ten platyfish in a fish tank. Each goldfish plays with ten red balls, while each platyfish plays with five white balls. What is the total number of balls in the fish tank?, ### Assistant: If there are 3 goldfish, and each is playing with ten red balls, then the number of red balls in the tank is 3*10=30
There are also ten platyfish playing with 5 white balls, there are 10*5= 50 white balls.
The total number of red and white balls in the fish tank is 50+30 = 80 
 So the answer is :  80