Can someone help me fill these in?
I've only managed to do one but the rest just confuses me

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a. about 4 b. about 8 c. about 40 d. about 21

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?

The equation of line wx is y=2x-5. write an equation of a line perpendicular to line wx in slopeintercept form the contains points (-1,-2)