Motion problems and exponential decay problem.

Hey guys, I am having some trouble with some calculus problems that I have for homework and I would like some help. If you guys choose to help answer my questions, would you mind posting the steps that you took in solving them as well?

An object initially at rest at (3,3) moves with acceleration a(t)=(2,e^-t). Where is the object at t=2?

After t years, 50e^-.015t pounds of a deposit of radioactive substance remains. The average amount per year NOT lost by radioactive decay during the second hundred years is?

A particle moves along a line with an acceleration a=6t. If, when t=0, v=1, then the total distance traveled between t=0 and t=3 equals?

Thanks in advance for the help!