Chapter 5.5, Problem 60E

Refer back to Example 5.31. Two cars with six-cylinder engines and three with four-cylinder engines are to be driven over a 300-mile course. Let X₁, … X₅ denote the resulting fuel efficiencies (mpg). Consider the linear combination

     $Y=(X_1+X_2)/2-(X_3+X_4+X_5)/3$

which is a measure of the difference between four-cylinder and six-cylinder vehicles. Compute P(0 ≤ Y) and P(Y ≥ −2). [Hint: Y = a₁X₁ + … + a₅X₅, with a₁ = 1/2 ,…, a₅ = −1/3.]