1)A water tank has a square base of area 2 square meters. Initially the tank contains 90 cubic meters. Water leaves the tank, starting at t=0, at the rate of 2 + 4 t cubic meters per hour. Here t is the time in hours. What is the depth of water remaining in the tank after 3 hours?

______meters

2)Disease A starts killing people in 1900 at the rate of 10000 people per year. Disease B starts killing people in 1910 at the rate of 20000 people per year.

(a) Sketch on one diagram for the period 1900 to 1950 how many people in total have been killed by each disease.

(b) How many people have died from these two diseases t years after 1900?

For disease A_______

For disease B when0t10

_______

For disease B when10t

_________

(c) In what year does the total number of people killed by the two diseases become equal?_____

(d) In what year does the total number of deaths first exceed half a million?______