If you are currently using a gas or electric pool heater, the savings from solar pool heating system will pay for itself in 2-3 years of installation. For example, the average system costs about $5,500 and it typically costs about $2,000 a year to heat a pool with gas.
In the United States, enrollment in AP Statistics classes has increased at a higher rate than in any other AP class. Students may receive college credit or upper-level college course placement upon the successful completion of a three-hour exam ordinarily administered in May.
AP classes mean Advanced Placement classes, which are more difficult than regular classes, but also count for more. If you take them in high school, you have the option to take the AP test, which, if you do well, will allow you to exempt part of your college course for that subject AP is short for Advanced Placement. After taking an AP class you can take a test that, if you score high enough, can give you college credit.