Answer: This population, the population is 45 fish.
Step-by-step explanation: This problem can be solved by a rule of three.
Last year there were 60 fish in the lake. That was 100, that is, decimal 1.
This year it decreased 25%. So there 100%-25% = 75%, that is decimal 0.75. So
60 fish - 1
x fish - 0.75
This population, the population is 45 fish.
