The complete solution of the ordinary differential equation $${{{d^2}y} \over {d\,{x^2}}} + p{{dy} \over {dx}} + qy = 0$$ is $$\,y = {c_1}\,{e^{ - x}} + {C_2}\,{e^{ - 3x}}\,\,$$ then $$p$$ and $$q$$ are

Using given data points tabulated below, a straight line passing through the origin is fitted using least squares method. The slope of the line is

A single die is thrown two times. What is the probability that the sum is neither $$8$$ nor $$9?$$

A lot had $$10$$% defective items. Ten items are chosen randomly from this lot. The probability that exactly $$2$$ of the chosen items are defective is