The Federal Helium Reserve held about 16 billion
cubic feet of helium in 2010 and is being depleted by
about 2.1 billion cubic feet each year.
a. Give a linear equation for the remaining federal
helium reserves, R, in terms of t, the number of
years since 2010.
b. In 2015, what will the helium reserves be?
c. If the rate of depletion doesn’t change, in what year
will the Federal Helium Reserve be depleted