In 1870 the average ground temperature in Paris was 11.8°C. Since then it has risen at a nearly constant rate, reaching 13.5°C in 1969.

(a) Express the temperature T (in °C) in terms of time t (in years), where t = 0 corresponds to the year 1870 and 0 ≤ t ≤ 99. (Give your answer in slope-intercept form.)

(b) During what year was the average ground temperature 12.7°C?

2 answers

T = {[(13.5 - 11.8) / 99] * t } + 11.8

plug in 12.7 for T , and solve for t
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