For this problem we need to find the decrease in value.
Decrease = Original Number - New Number
Then to find the percentage
% Decrease = Decrease (from above) / Original Number * 100
Let's use the numbers you gave.
Decrease = Original Number - New Number
$39.95 = $109.45 - $69.50
So, the price went down by $39.95
We are not done yet, we need to find the percentage.
% Decrease = Decrease (from above) / Original Number * 100
So, it would be
36.50% = ($39.95 / $109.45) * 100
36.50% = 0.3650 * 100
It had 36.50% off the original price.
I hope this helps.
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