Suppose a railroad rail is 4 kilometers and it expands on a hot day by 11 centimeters in length. Approximately how many meters would the center of the rail rise above the ground?

Solve each quadratic equation by factoring and using the zero product property. n^2 - 49 = 0

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25