Answer:
Initial Number = x = 21
Number after it is decreased = y = 15
Total decrease form initial to the current number = z = x-y = 21-15 = 6
% of decrease = (z/x) * 100 = (6/21)*100 = 600/21 = 28.5714286 = 28.6 ( correcting it to 10th place)
Step-by-step explanation:
