A dress on sale in a shop is marked at $D. During the discount sale its price is reduced by 15%. Staff are allowed a further 10% reduction on the discounted price. If a staff member buys the dress what will she have to pay in terms of D ?

Question

anonymous · Answer

Know that the prices are reduced by a percentage of D. So if we get 10% off, it just means that the price we pay is the original D minus the percentage. We can write this as D - 0.10D.

D(new) = D(original) - 0.10D with a 10% reduction.

In the problem, however, we have two deductions from the original price. One of which is 10%, the other of which is 15%. If you add these deductions you can effectively get 25% off the original price.

So:

D(new) = D(original) - (0.25D)

Now we simplify: 
D(new) = D - 0.25D

D(new) = 0.75D