What is a ratio? i am confused

What is 81.50:25?

Sean read 1/5 of a book in 1 1/2 hours. how long will it take sean to read 1/2 of this book? enter your answer as a mixed number in simplest form in the box.

Billy the friendly Robot uses 50 N of force to lift a box 2 meters in the air. How much work did Billy perform? (this question is also partially science but it says to use algebra to answer the question)

What is the slope-intercept form of the equation y - 7 = - 5/2 (x+4)

Question 4: You are splitting the bill for repairs to your apartment, and each roommate will pay 20% of the $6,000 bill. How much do you owe? What is 10% of the total repair bill? Your answer What will each roommate's 20% share be?

2x + 3y = - 14 y = 6x + 22

3$ is what percent of $12

If f (x) = x + 1/x, find f (1+3i)

The area of the small triangle is 10.5 meters squared and the area of the larger triangle is 94.5 meters squared. if the altitude of the large triangle is 9, what is the altitude of the smaller triangle

A rental car cost a total of $282 for a week. six students shared the car. how much should each pay? a. $48 b. $35 c. $50 d. $47