Answer:
Decrease 80%
Step-by-step explanation:
[tex]percentage \: change \\ = \frac{5 - 1}{5} \times 100 \\ \\ = \frac{4}{5} \times 100 \\ \\ = 4 \times 20 \\ \\ = 80\% \\ [/tex]
Since, new cost is less than the original cost, hence there will be a decrease of 80%.
