NEED HELP FAST! Giving BRAINLIST geometry

please no links and if you can I would appreciate if you could explain how to do them

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

How to find the exponential function y=ca^x, with points (1,2) and (2,1)

Yvaries directly as x. y =90 when x=6. find y when x=13