Which expression shows the simplified form of (8 r Superscript negative 5 Baseline) Superscript negative 3?

8 r Superscript 15
StartFraction 8 Over r Superscript 15 Baseline EndFraction
512 r Superscript 15
StartFraction r Superscript 15 Baseline Over 512 EndFraction

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?

Mozart lenses inc. recently introduced seelites, a thinner lens for eyelasses. of a sample of 800 eyeglass wearers, 246 said they would purchases their next pair of eyeglasses with the new lenses. lenses inc. estimates that the number of people who purchase eyeglasses in a year is 1,700,000. most eyeglasses wearer buy one new pair of eyeglasses a year. what is the annual sales potential for the new lenses.

Could somebody me with this radical simplification?