Suppose the lifetime of a van has a uniform distribution over [3,10]. Mr Smith buys a new van as soon as his old van either breaks down or reaches the age of 8 years. A new van costs $20,000 and an additional cost of $1000 is incurred whenever a van breaks down. Assume that a T years old car in working order has an expected resale value of 20,000[(1000T)/2]. What is Mr Smith\'s long-run average cost? Solution L= Lifetime of the van L~ U(0,10) I[A] is the indicator function which takes the value 1 if A is true and 0 otherwise. Long run cost of Mr. Smith = Cost incurred* I[ old van breaks down before reaching the age of 8 years] + Cost incurred * [ old van reaches the age of 8 years] Thus Expected long run cost = Cost Incurred* P[old van breaks down before reaching the age of 8 years]+ Cost incurred * P[old van survived reaches the age of 8 years] = $ 21000* P[ L < 8 ] + ${20000-1000*8/2}* P[ L > 8] = $ 21000* (8-3)/(10-3) + $16000 * (10-8)/(10-3) = $ 21000* 5/7 + $ 16000* 2/7 = $ 15000 + $ 4571.4 =$ 19571.4 Please rate and reward :).