20 cos シ is your answer
Step-by-step explaination
Answer: THEY WERE ALL EATEN BY A SHARK
Ok, for real, the answer is 12, divide 84 by 7, so each week he gets 12 new fishes
66,000*0.15
9,900*5
49,500+66000
The answer is 115.500
I'm not sure if the whole thing is correct, but here is the easier way:
66,000(1+1.15)^5