Question 1009585
45 is incorrect because you have: the price of the car is 100% and it is reduced by 25%. 100-25= 75%. 
Now you have a further reduction of 20%, but note, it's 20% off of 75%, not of the original full price of 100%.
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75%-(75*20)= 75-15= 60% is the new price of the car, and 100-60= 40% is the total reduction in price.