The number of asthma sufferers in the world was about 84 million in 1990 and 130 million in 2001. Let $N$ represent the number of asthma sufferers (in millions) worldwide $t$ years after 1990.

(a) Write $N$ as a linear function of $t$. Use exact values in your formula, not decimal approximations.
$N(t) =$ million people help (formulas)

(b) Write $N$ as an exponential function of $t$. Use exact values in your formula, not decimal approximations.
$N(t) =$ million people help (formulas)

(c) How many asthma sufferers are predicted worldwide in the year 2012 with the linear model?
million people. (Round to the nearest 0.01 million people.) help (numbers)

(d) How many asthma sufferers are predicted worldwide in the year 2012 with the exponential model?
million people. (Round to the nearest 0.01 million people.) help (numbers)