If Karen's 45 minute lunch break ended at 12:30 P. M., what time did her lunch break begin?

Which equation represents a proportional relationship that has a constant of proportionality equal to 1/5

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?

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 : /