Iam a multiple of 20. i have 3 digits, my hundreds digit and tens digit add to make 9. half of me is less than a 100 ,what number am i ?

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

If using the method of completing the square to solve the quadratic equation x 2 + 16 x + 24 = 0 x 2 +16x+24=0, which number would have to be added to "complete the square"?

The life, in years, of a certain type of electrical switch has an exponential distribution with an average life b = 2. if 100 of these switches are installed in dif- ferent systems, what is the probability that at most 30 fail during the first year?