Answer:
50%
Explanation:
First, to find a percentage, you divide the part out of the whole (numerator out of the denominator in a fraction);
4 ÷ 8 = 0.5
Once you have your decimal number, you need to move the decimal point 2 spaces to the left to turn it into a percentage;
0.5 = 50
Therefore, the percent decrease is 50%.