If a is the greatest common factor of 6, 21, and 36, and b is the lowest prime number, what is the sumof a and b?

You have 17 cats that live in houses on your street, 24 dogs, 3 fish, and 4 hamsters. what percent of animals on your block are dogs?

What is the value of x in the equation 1.5x+4-3=4.5(x-2)?

Apassenger train and a freight train leave san jose at 3pm, traveling in the same direction. the passenger train is going three times as fast as the freight train. at 6pm they are 240 miles apart. how fast is each travelling? explain your answer and show your