What is the area of a rectangle with an area of 3.1 mm and a width of 2.4 mm

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer