Is capacity the same as amount

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under

Awasher and a dryer cost $701 combined. the washer costs $51 more than the dryer. what is the cost of the dryer?

Ade and abc are similar. which best explains why the slope of the line between points a and d is the same as the slope between points a and b?