The Purplemath Forums

It seems that in some word problems, it's not necessary to change a percent to decimal, but in others it is. Below are some examples of what I mean. -------------------------------------- Here is a word problem where percent to decimal is necessary to solve the word problem algebraically: Earnings -...

Can someone help me sort this problem out as a formula, while explaining the reasoning? Also, could someone classify what kind of word problem this is? Thanks! A thief steals a number of rare plants from a nursery. On the way out, the thief meets three security guards, one after another. To each sec...

If f(x + y) = f(x) + f(y) and f(1) = 3, find f(2), f(3), and f(4). Is f(x + y) = f(x) + f(y) for all functions? I don't understand what f(x + y) = f(x) + f(y) is. Is it saying that if you plug in 2 numbers (x + y) into the function f, the value returned will be what would be returned by the same fun...

The math question in my book that I'm inquiring about has a picture, so I took a picture and uploaded the question. It's #65. http://uploadpic.org/v.php?img=wBAwPTzp7I I've only got two linear equations in 3 variables. I needed one more to create a system of 3 equations in 3 variables. This is what ...

The toll to a bridge is $3.00. A three-month pass costs $7.50 and reduces the toll to $0.50. A six-month pass costs $30 and permits crossing the bridge for no additional fee. How many crossings per three-month period does it take for the three month pass to be the best deal? The answer is: more than...