To determine which window cleaner is most effective, Thad washes half of the windows in his house with one brand and the other half with a different brand. He then compares the results to draw a conclusion about which cleaner is most effective. What kind of statistical study did Thad conduct?

A.

survey

B.

observational study

C.

theoretical study

D.

experiment

the answer for the question is D,experiment

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m