"Published in Newark, California, USA"
Aling Etang bought several dozen eggs at PHP 600. Because of poor storage, 2 dozens were spoiled and had to be thrown away. Nonetheless, she realized a profit of PHP 154 by charging PHP 3 more than she paid per dozen. How many dozen eggs did she buy?
Solution:
The given word problem is about money and investment problem with profit, of course where she thrown 2 dozens of eggs but she earned a profit by charging more than she paid per dozen in order to save her capital or investment from loss. Let's analyze the problem as follows
Let x = be the price of a dozen of eggs, in PHP
y = be the number of dozens of eggs
From the first word statement, "Aling Etang bought several dozen eggs at PHP 600", the working equation will be
From the next word statement, "Because of poor storage, 2 dozens were spoiled and had to be thrown away", the working equation will be
From the next word statement, "....by charging PHP 3 more than she paid per dozen," the working equation will be
The overall working equation for this problem is
Profit = Total Amount Sold - Total Amount Invested
but
The above equation becomes
Divide both sides of the equation by -2, we have
Multiply both sides of the equation by x, we have
Use Quadratic Formula to solve for the value of x, we have
To calculate the price of a dozen of eggs, choose the positive sign as follows
Therefore, the price of a dozen of eggs is PHP 10.
Consider the first equation
if x = 10, then
Therefore, Aling Etang bought 60 dozens of eggs.
Note: PHP means Philippine Pesos and the prices mentioned in the word problem above was in 1985.