Emissions of heat-trapping carbon dioxide (CO₂) reached an all-time high of 36.9 gigatons in 2014, a 2.5% increase over 2013. The International Energy Agency said this further reduces the chance that the world could avoid a dangerous rise in global average temperature by 2020.

(a) If the discharge of CO₂ continues at the same 2.5% rate per year for the next 6 years, how many gigatons will be released in 2020,

(b) What will be the total percentage increase between 2014 and 2020?