Create a linear system to model this situation A collection of nickels and dimes contains four times as many dimes as nickels The total value of the collection is 20.25$

hrs/house

Step-by-step explanation:

Rate is the amount of work done per unit of time;

  Let Cara's rate  = C

   Let Jena's rate  = J

        C + J  = 4  ------ i

Now;

  Working alone:

             Jena takes twice as long as Cara

                          J  = 2C  ---- i

How long does it take Cara to clean a house alone

           C + J  = 4

             J = 2C

        C + 2C = 4

           3C = 4

              C = hrs/house