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SAT Math: Arithmetic

Percent Change

In 2002, a dozen eggs cost an average of $1.03.  In 2012, the average price rose to $1.80 per dozen.  By approximately what percent did the price of eggs increase?.   

A.  41%

B.  71% 

C.  73%

D.  74% 

E.  77% 

 

Knowsys Method

Read the question carefully.  This question has to do with change.

Identify the bottom line.   % change = ?

Assess your options.  You could use a complicated formula for change that you learned in school, but for SAT questions like this, a simple formula will suffice.  It doesn't matter whether the change is an increase or a decrease, all you need to do is divide the difference by the original.

Attack the problem.  

The difference between these two prices: $1.80 - $1.03 = $0.73

The original price: $1.03

The percent increase:  

diff-orig.PNG

This answer is the percent change (in this case an increase): .71 = 71% .

Loop back.  The question asked for an approximate number, so you are justified in rounding.

 

The correct answer is  (B).

This is a medium level question.

 

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