If a1=2 and an=3an-1 then find the value of a5

What situation is an example of an observational study

Under normal conditions, 1.5 feet of snow will melt into 2 inches of water. during a winter season high in the mountains, 301 feet of snow fell. how many inches of water will there be when the snow melts?

If you have 12 feet of string and you cut it into equal length of 5 inches each how much string will be left