I need help with these question, could you do it on paper so its easy for me to understand

Investments, Mixtures 1. Complete the following statements. (a) The interest, after one year, on $2000 at 10% is (b) The interest, after one year, on $300 at 9% is (c) The interest, after one year, on $3000 at 12% is (d) The interest, after one year, on $x at 7% is 2. Armin invested $1000, part at 8% per annum (year) and the remainder at 9% per annum. After one year her total interest from these investments was $84. How much did she invest at each rate? 3. Athar invested $8000, part at 9% per annum and the remainder at 10% per annum. After one year his total interest from these investments was $740. How much did he invest at each rate