Question

The power ratings of several motors are listed in the table.

A 2 column table with 3 rows. The first column is labeled motor with entries, brand X, brand Y, brand Z. The second column is labeled Power in watts with entries 7460, 7650, 7580.
An advertising agency writes marketing material for a new motor (Brand W) that has a power rating of 7,640 W. Which statement comparing the motors can they truthfully use?

Brand W motor can finish any job faster than Brand Y motor can.
There’s not a more powerful motor available.
Brand W motor does more work each second than Brand X or Brand Z.
Every second, Brand W motor does 7,640 N of your toughest work.

Answer 1

Only the third statement is truthful.

- 1 is false: Brand Y is 7,650 W, which is slightly more powerful than Brand W (7,640 W), so W cannot be guaranteed to finish any job faster than Y.
- 2 is false: Brand Y (7,650 W) is more powerful than Brand W (7,640 W).
- 3 is true: 7,640 W > 7,460 W (X) and > 7,580 W (Z), so Brand W does more work per second than X or Z.
- 4 is false/meaningless: watts measure energy per time (J/s). Saying “7,640 N each second” mixes units — it would be 7,640 J/s (watts), not newtons.