Two Models $R _ { 1 } = 7.21 + 0.58 t$

Two models, $R _ { 1 } = 7.21 + 0.58 t$ and $R _ { 2 } = 7.21 + 0.43 t$ , are given for revenue (in billions of dollars per year) for a large corporation. Both models are estimates of revenues for 2007 through 2011, with t = 7 corresponding to 2007. Which model is projecting the greater revenue? How much more total revenue does that model project over the five-year period?

A) The model $R _ { 1 }$ projects greater revenue than $R _ { 2 }$ . $\$ 8.75$ billion
B) The model $R _ { 2 }$ projects greater revenue than $R _ { 1 }$ . $\$ 7.75$ billion
C) The model $R _ { 1 }$ projects greater revenue than $R _ { 2 }$ . $\$ 6.75$ billion
D) The model $R _ { 1 }$ projects greater revenue than $R _ { 2 }$ . $\$ 10.75$ billion
E) The model $R _ { 2 }$ projects greater revenue than $R _ { 1 }$ . $\$ 16.75$ billion