Question

U.S. oil reserves are estimated to be 2.2x1010 barrels (42 gal per barrel). We use about 7.2x108 barrels per year. At this rate, how long will US oil reserves last? (Round to the nearest year)

Answer 1

Is it 30 years?

Answer 2

dividing

\(\huge \frac{2.2*10^{10}}{ 7.2*10^8}\)

you get 30.55, right ?

Answer 3

Yes, to the nearest year - then it is 30, thank you.

Answer 4

no... rounding 30.55 to nearest year will give 31..