help with algebra

 

   All members of our painting team paint at the same rate.     

   If 20 members can paint a 2000 square foot wall in 40 minutes, then how long would it take     

   the 20 members to paint a 6000 square foot wall, in minutes?     

 

   20 members   ==>>    paint 2000 ft² / 40 min  =  50 ft² per min     

   20 members   ==>>    paint 6000 ft² /  x          =  50 ft² per min     

                                               6000 ft²                =  50 ft² per min • x     

                                          6000 ft² / 50 ft²/min  =  x     

                                                                        x  =  120 min     

 

   Another way to do it is to consider the 6000 ft² wall as equivalent to three 2000 ft² walls     

   So, because one wall takes 40 minutes, three walls would take (3 • 40 min) = 120 min     

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