the total amount on a loan of 6,000 for 150 days is 210.50. using the ordinary interest metnod. what is the rate on this loan? rounded to nearest hundredeth.

There are several sites in here that will show you how interest is calculated:

http://www.google.com/search?rlz=1C1GGGE_enUS379US379&sourceid=chrome&ie=UTF-8&q=how+to+calculate+interest

Once you have given this a try, post what you come up with so that a math tutor can check your work.