82. P(X>650)=\frac{700-650}{700-300}=\frac{50}{400}=\frac{1}{8}=0.125. P(400 <650)> 84. \(X = the useful life of a particular car battery, measured in months. X is continuous. The cdf is \...82. P(X>650)=\frac{700-650}{700-300}=\frac{50}{400}=\frac{1}{8}=0.125. P(400 <650)> 84. \(X = the useful life of a particular car battery, measured in months. X is continuous. The cdf is P(T<t)> \(P(T<2)=1-1-e^{-\frac{2}{7}} \approx 0.2485. P(T>15)=1-P(T<15)=1-\left(1-e^{-\frac{15}{7}}\right) \approx e^{-\frac{15}{7}} \approx 0.1173. P(T>15 | T>10)=P(T>5)=1-\left(1-e^{-\frac{5}{7}}\right)=e^{-\frac{5}{7}} \approx 0.4895.