It takes 16 minutes for 9 people to paint 8 walls. how many does it take 4 people to paint 6 walls

The things you can apply to complete this job is workers and time. The job being accomplished is painted walls. This problem defines two jobs. The rate for each of the jobs will be the same. The first job rate is: R=(7 wkr)•(42 min)/(6 walls)R= 49 wkr-min/walls or 49 worker-minutes per wall. This means one worker can paint one wall in 49 minutes. If you think about this job if 7 workers take 42 minutes to do 6 walls it will only take them 7 minutes to do one wall. And it will take one person 7 times as long to do a job as 7 people working together.  This first job rate equals the second job rate R=(8 wkr)•(t )/(8 walls)R=1 t wkr/wall where t is the time to do the second job. Setting the two rates equal to each other and solving for t. t=49 minutes It makes sense if one worker can paint one wall in 49 minutes then 8 workers can paint 8 walls in the same time.  

For the first question the answer is a, for the second c, for the third d, for the 4th b, for the 5th a