water and wind current equations/problems

how would you solve this;

a boat goes 36km downstream in the same amound of time that it takes to go 24 km upstream. if the current is flowing at 3 km/h, what is the rate of the boat in still water?

also how would you solve this

Jane is planning a 3 hour trip down the river and back to her starting point. She knows she can paddle in still water at 3 mi/h and that the rate of the current is 2 mi/h. How much time can she spend going downstream and how far downstream? upstream?

I know how to do other wind and water problems in order to find the speed of someone (or a boat...) in still water and the rate of that current if given the time and distance. i already know the formulas for Distance, Rate, and Time i just can't seem to get how these problems are meant to be solved.

thanks

Hints; 1st question:
b = boat speed
36km travelled @ (b+3), 24km travelled @ (b-3), same time for each

2nd question:
h hours travelled @ 3+2=5, (3-h) hours travelled at 3-2=1