If Nora (N) has 4 goldfish, you substitute N=4 into the previous equation to find out how many goldfish Sammie has.
> S= 3 x 4 = 12
The next part of the question is asking you how many goldfish do Sammie and Nora have in all. If Sammie has 12 goldfish and Nora has 4 goldfish, the equation would be 12 + 4= 16
If you add 87.84, 85, and 100 you get 272.84. Once you divide that by 3 you get 90.946, which would be your test average if you score 100 on your next test.