Answer
$R_{1}$ projects greater revenue;
$R_{1}$ projects 11.375 billion dollars more than $R_{2}$
Work Step by Step
We can start off by integrating the functions to get area under the curve and projected revenue
The time interval is between 2015 and 2020 with 2015 corresponding to t=15
So the bounds of our integral are lower limit: 15 upper limit: 20
$R_{1}$: $\int_{15}^{20}$(7.21+0.58t)dt = 86.8 billion dollars
$R_{2}$: $\int_{15}^{20}$(7.21+0.45t)dt = 75.425 billion dollars
$R_{1}$ has greater area under the curve and therefore projects greater revenue
$86.8-75.425=11.375$
