Rumination 4: In 2015, US natural gas consumption was 778 billion cubic meters and European
natural gas consumption was 1003.5 billion cubic meters. Additionally, US consumption increased
by 3% that year while the European consumption fell by 0.3%. We'll assume these rates continue
indefinitely.
(a) List out the first four terms of the sequence, an, giving US consumption of natural gas n years
after 2014, and write down a formula for an. Note, a₁ will then be the gas consumption in
2015.
(b) List out the first four terms of the sequence, bn, giving European consumption of natural
gas n years after 2014, and write down a formula for bn. As before, note b₁ will be the gas
consumption in 2015
(c) Determine the first year that US yearly gas consumption will exceed European consumption.