What is the slope of a price is starting at $54 and decreases weekly by $2.50?

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?

Ammonia molecules have three hydrogen atoms and one nitrogen atom. how many of each atom arein five molecules of ammonia

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'