Fraction of Original Price

[nycmathguy]

Math 004 sample test questions for anyone seeking NYS certification as a high school math teacher. This is just one of several exams required for NYS high school teacher certification.

I should be able to fly through this type of problem. The fact of the matter is NO!

Let f = fraction of the original price.

f - 0.20f = 0.25f

Yes?

 

[MathLover1]

let original price be x:

When the dress is marked down by 20%, the cost of the dress is 80% of its original price; thus, the reduced price of the dress can be written as (80/100) x,or (4/5) x, where x is the original price.

so, (4/5) x is the reduced price

When discounted an extra 25%, the dress costs 75% of the reduced price, or

(75/100) (4/5) x, or (3/4) (4/5 )x, which simplifies to (3/5) x.

So the final price of the dress is (3/5) of the original price.

 

[nycmathguy]

let original price be x:

When the dress is marked down by 20%, the cost of the dress is 80% of its original price; thus, the reduced price of the dress can be written as (80/100) x,or (4/5) x, where x is the original price.

so, (4/5) x is the reduced price

When discounted an extra 25%, the dress costs 75% of the reduced price, or

(75/100) (4/5) x, or (3/4) (4/5 )x, which simplifies to (3/5) x.

So the final price of the dress is (3/5) of the original price.

1. Are you saying that 80% came from 100% - 20%?

2. Are you saying that 75% came from 100% - 25%?

You know what this means, right? It means if I were planning to take the Math 004 test to be certified as a high school math teacher in NYS, I would fail. Mira, how in the name of God can this be a reality for me after going through an entire precalculus textbook with you and before you with other online math experts? Am I wasting time with this subject?