The annual interest on an $18,000$⁢18,000 investment exceeds the interest earned on a $5000$⁢5000 investment by $1148$⁢1148.  The $18,000$⁢18,000 is invested at a 0.6%0.6% higher rate of interest than the $5000$⁢5000.  What is the interest rate of each investment?

Two investments totaling $18,000$⁢18,000 produce an annual income of $1370$⁢1370.  One investment yields 7%7% per year, while the other yields 8%8% per year. How much is invested at each rate?

Two investments totaling $63,500$⁢63,500 produce an annual income of $3250$⁢3250.  One investment yields 4%4% per year, while the other yields 6%6% per year. How much is invested at each rate?

A person lends 40% of his sum of money at 15% per annum, 50% of rest at 10% per annum and the rest at 18% per annum rate of interest. What would be the annual rate of interest, if the interest is calculated on the whole sum ?

Sasha placed $400 in an investment that earns an annual interest rate of 6%. If the investment interest is compounded annually, how much more interest is earned in the second year than in the first year?

Assume the total cost for invest in a business will be $280,000 in 18 years. You presently have $45,000 to invest. What annual rate of interest must you earn on your investment to cover the cost?