Idont understand the question simplify 5n+13−8n−9

Tyler enjoys the fish so much that after his birthday his family decides to take him to a famous aquarium a tank at the aquarium is similar to his tank with the scale factor of 8 how many times greater is the volume of the tank at the aquarium than the volume of tyler tank

If p(a) = 0.70 and p(b) = 0.20, then a and b are independent events if

Siri can type 90 words in 40 minutes about how many words would you expect her to type in 10 minutes at this rate