Is k=4 a solution to the equation 1/2k=8

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?

You got a job selling magazines door-to-door. you are paid $100 per day plus $1.50 for each magazine you sell. which recursive formula models this situation?

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /