PreCalculus
posted by L.Bianchessi .
A town has a population which is growing linearly. In 1970 its population was 36,000 while in 1985 its population was 63,000. Find a formula for its population P(t), where t=0 corresponds to the year 1970.

do it in thousands
(0, 36) , (15,63)
(y36)/x = (6336)/15
You take it from there.