Three bells ring at the intervals of 20, 30 and 40 minutes respectively. Find the least interval of time after which they ring at a time

Find parametric equations for the line tangent to the curve of intersection of the surfaces at the given point. surfaces: xsquared2plus+2yplus+2zequals=1212 yequals=33 point: left parenthesis 1 comma 3 comma five halves right parenthesis

Rosy waxes 2/3 of her car with 1/4 bottle of car wax. at this rate, what fraction of the bottle of car wax will rosey use to wax her entire car

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?