I have an exam next week and have no idea how to answer questions like this, though I've been told that there is one on the exam ... it says:Richard has $10,000. He invested part of it in a term deposit paying 4% per annum, and the remainder in bonds paying 5% per annum. If the total interest after one year is $440, how much did he invest at each rate?I know the answer is $6,000 at 4% and $4,000 at 5%, but could someone explain to me how to figure out how to do these questions? I would really appreciate it, I have no idea how to label them so I can solve it ... thanks!