You light both a 4 hour candle and a 5 hour candle at the same time. After how long will the 5 hour candle be twice the size of the 4 hour candle? Just for your info, the answer is not a whole number, and for that reason is not 3 hours. Simple Algebra can handle this problem.
This puzzle is dedicated to my grandfather Jose Ismael who first composed it when he was in junior high school, long time ago...
The area for a circle is given by the formula A = pi * r ^2, where pi =3.1415927... and r is the radius. What's the formula for the area of the circle's cousin, the elipse? Some Calculus will help on this one.
A man stands and sees a plane in the sky. His angle of sight to the plane is 45 degrees. Another man who stands 20 feet behind him, can also see the plane, but his angle of sight to the plane is 30 degrees. How high is the plane flying? This one is for Trigonometry fans.