Brainliest + points

can someone ? kind of struggling. would you explain

in 2008, adam lopez set a world record by singing the highest note ever recorded, a c8. that is four octaves above middle c and not on a normal piano keyboard. what is the frequency to the nearest hertz of this musical note if its period is 0.00024?

a.
1,873 hertz

b.
2,631 hertz

c.
3,845 hertz

d.
4,167 hertz

I'm confused on this could anyone me and show me what i need to do to solve it.

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?

Sally deposited money into a savings account paying 4% simple interest per year. the first year, she earned $75 in interest. how much interest will she earn during the following year? show your work and explain your reasoning in the space provided below.