The price of gas keeps going up. In California, most gas stations now charge over $4 even for the lowest octane gasoline. Hybrid cars cost more, but are more energy efficient than most standard gasoline-only cars. Hybrid cars are also better for the environment. Are they better for your wallet as well? Let’s figure out the break-even time for a hybrid car, and how much money you could save over the lifetime of a hybrid car.

## Archive for the ‘Problem of the Month’ Category

## Problem of the Month – April 2011

Posted in Education, Math, Problem of the Month, Teaching Math, tagged energy efficient, gas price, gasoline, hybrid cars, problem of the month on April 23, 2011| Leave a Comment »

## Problem of the Month – March 2011

Posted in Education, Math, Problem of the Month, Teaching Math, tagged home improvement, online math, problem of the month, problem solving practice, real-world problem, square feet, tiles on March 24, 2011| Leave a Comment »

Sally wants to do a home improvement project. Her kitchen floor is in bad shape and she wants to retile the floor. She needs to figure out how many tiles to buy. Her kitchen measures 15’ by 20’. She will use tiles that measure 13” by 13”. The tile costs $3.50 per square feet. How many tiles does she need to buy and how much will the tiles cost?

## Problem of the Month – February 2011

Posted in Math, Problem of the Month, Teaching Math, tagged compound interest, grow rate, Netflix, online math, problem of the month, problem solving practice, real-world problem, revenue on February 10, 2011| Leave a Comment »

Last month we talked about compound interest. This month we will use the compound interest concept and do a real-world problem, a kind of exercise often performed by financial analysts.

Netflix is a company that provides movies for viewing, either by streaming online or by mailing a DVD to your home. As a company, it has done extremely well. Its revenue (the total amount of money it receives from all of its customers) was $1.21B (billion) in 2007, $1.36B in 2008, and $1.67B in 2009. Here is the problem: What was Netflix’s average revenue growth rate from 2007 to 2009? If it continues to grow at that rate, how big will the revenue be in 2015?

## Problem of the Month – January 2011

Posted in Education, GoldStudent, Problem of the Month, Teaching Math, tagged compound interest, interest, Math, math problem, problem of the month, rate of return on January 14, 2011| Leave a Comment »

Compounding interest is a very powerful concept. It can really hurt you, such as when you don’t pay off your credit card bill and the interest payment keeps getting bigger and bigger. It can also help you if you save money and manage it well enough to earn a steady return over many years.

If you start with $1000.00, how much will this become after 10 years if the rate of return is 5%?

## Problem of the Month – December 2010

Posted in Math, Problem of the Month, Teaching Math, tagged christmas trees, estimation problem, Math, math problem, problem of the month on December 27, 2010| Leave a Comment »

We have estimated that each year about 100 million Christmas trees are sold in the U.S.. I was wondering how much land it would take to plant and grow these trees. Can you estimate this number?

Let’s assume that it would take 7 years for a tree to grow big enough to be cut down (6 to 12 years is a reasonable range).