Could you please help me to understand?

Ali invested $2,370 for 314 days at a simple interest rate of 2.50% p.a. How much more or less interest would he have earned on the investment if his money was growing at a simple interest rate of 3.00% p.a. instead of 2.50% p.a.?

Helen held a loan of $3,600 for 5 months and was charged interest of $129.00. What was the annual simple interest rate on this loan?

If $13,376.39 was the interest earned on lending $100,400.00 for 8 years, what was the quarterly compounding nominal interest rate charged on the loan?

A bank charges Solid Co. an interest rate of 4.75% compounded quarterly on its line of credit. If the effective interest rate increased by 0.75%, calculate the new interest rate compounded quarterly.

A manufacturing company has 170 production people, 20 quality inspectors, 16 sales people, 7 marketing people, and 30 people in other departments such as HR, Finance, etc.

a.What percent of the total employees are quality inspectors?

b.If 5.88% of the production people quit their jobs, what percent of the total remaining employees are quality inspectors?

Lucy's portfolio of shares comprised of investments of $9,400 in the telecommunications industry and $13,200 in the information technology industry. The market price of her telecommunications shares decreased by 45% and that of information technology increased by 60%.

a.Calculate the total market value of her investments after the changes.

b.By what percent did the total market value of her investments change?