for dtoms remaining in a sample is 79%, how old is the sample? 4. The volume of water, V litres, in a tank t minutes after the tank has started to drain, is given by the V(t) = 1000(25-t ), Osts 5 . How fast (litres/min) is the water draining after 4 minutes? 5. An object starts at t = 0 and moves in a pre-determined path. It's distance, d in metres, from 4t dd = its starting point at time t seconds is given by How far is the object from the starting point when it's velocity is 0