What Is the Payback Period of the F-22 Raptor Project

What is the payback period of the F-22 Raptor project? The Lockheed Martin/Boeing F-22 Raptor is a stealth fighter aircraft. It was designed primarily as an air superiority fighter, but it is also capable of ground attack and other roles. Lockheed Martin Aeronautics is the prime contractor and is responsible for the majority of the airframe, weapon systems and final assembly. Lockheed Martin invested over $10B on design and manufacturing for the aircraft. Assume that those investments were paid for on Jan 1, 2003. Each aircraft will be sold for $350M and the variable cost of building each airplane is $300M. Assume that 70 aircraft will be sold each year for 5 years. Assume that revenues and costs occur uniformly throughout the year. What is the payback period of the project? $$\begin{array} { | c | c | c | c | } \hline \text { Date } & \text { Investments } & \text { Revenues } & \text { Costs } \\\hline \text { Jan. } 1,2003 & - \$ 10 \mathrm {~B} & & \\\hline \text { Dec. } 31,2003 & & \$ 24.5 \mathrm {~B} & \$ 21 \mathrm {~B} \\\hline \text { Dec. } 31,2004 & & \$ 24.5 \mathrm {~B} & \$ 21 \mathrm {~B} \\\hline \text { Dec. } 31,2005 & & \$ 24.5 \mathrm {~B} & \$ 21 \mathrm {~B} \\\hline \text { Dec. } 31,2006 & & \$ 24.5 \mathrm {~B} & \$ 21 \mathrm {~B} \\\hline \text { Dec. } 31,2007 & & \$ 24.5 \mathrm {~B} & \$ 21 \mathrm {~B} \\\hline\end{array}$$

A) 5 months
B) 2.86 years
C) 3.45 years
D) 3.39 years
E) 7.8 years