A tank contains 200 gal of salt water at a concentration of 5 lb/gal. Salt water at a concentration of 1 lb/gal is pumped into the tank at a rate of 2 gal/min, and the well-stirred mixture runs out at a rate of 2 gal/min. How much salt is in the tank after t min?

step-by-step explanation:

assume that you have 3 different side lengths.   apply the pythagorean theorem here:   square each of the two shortest sides; call them a and b, so that their squares are a² and b².   also square the longest side, calling the result c².

now, if a² + b² = c² is true, the triangle is a right triangle; otherwise it is not a right triangle.