81-1= 80
80 / 2 = 40
D = 40
So:
40(2) = 81 - 1
Old price: p1 = $ 3.90;
New price: p2 = $ 3.40.
The percentual decrease is given by
d(%) = [ (p2 - p1) / p1 ] * 100 %
d(%) = [ (3.40 - 3.90) / 3.90 ] * 100 %
d(%) = [ - 0.50 / 3.90 ] * 100 %
d(%) = - 0.128 * 100 %
d(%) = - 12.8 % (approximately)
So the price fell 12.8 % approximately.
I hope this helps. =)
Answer:
C
Step-by-step explanation:
