Suppose the world’s oil reserves in 2014 are 1,820 billion barrels. If, on average, the total reserves are decreasing by 25 billion barrels of oil each year:

a. Give a linear equation for the remaining oil reserves, R, in terms of t, the number of years since now.

b. Seven years from now, what will the oil reserves be?

c. If the rate at which the reserves are decreasing is constant, when will the world’s oil reserves be depleted?