How do I write the equation "x works twice as fast as y" ?

Answer 1

Answerer #1 is correct. x = 2y

I meant to vote thumbs up on him, but clicked thumbs down instead. I therefore want to clarify here for the benefit of the person who asked this question. Even though a bunch of people said 2x=y, and only your first answer has a thumbs down, do not let that mislead you! The correct answer is x = 2y.

Look at it this way, one of x is worth two of y, since x works twice as fast as y. So, x = 2y is the correct way to express this. Another way to look at this is that it takes two y's to work as fast as one x.

I guess I'd better go "thumbs down" all those wrong answers, just to be safe!

Answer 2

It depends on whether x and y are representing speed or time.

If you're talking how many seconds it will take them to finish a certain amount of widgets, then 2x = y

If you're talking about how many widgets they make per second, then x = 2y

Answer 3

x works twice as fast as y:
2*Tx=Ty,

where ,Tx=time taken by x in doing a particular job
Ty=time taken by y in doing a particular job.

(It means if y is doing a job in 5 minutes, x can do the same job in 2.5 minutes.)

Answer 4

2x = y

Answer 5

2x=y

Answer 6

2y=x

Answer 7

x=2y

Answer 8

2x=y or y=2x