4) At lunch, you volunteer to go out to buy sandwiches. You get 6 chicken sandwiches and 6 ham sandwiches for $30. Later that afternoon, everyone gets hungry again. You go to the same
shop and buy 4 chicken sandwiches and 8 ham sandwiches for $30.60 What was the price of
each sandwich?
(assume tax is included in the totals)

Cost chicken sandwich is  $2.35

Cost of ham sandwich is $2.65

Step-by-step explanation:

Let the cost of chicken sandwiches  = c

Let the cost of ham sandwiches = h

Number of chicken sandwiches = 6

Number of ham sandwiches  = 6

So,  

               6c + 6h = 30 (I)

Number of chicken sandwiches on second round  = 4

Number of ham sandwiches on second round  = 8

             4c + 8h = 30.6 (ii)

We have two sets of of equations, let us solve;

            6c + 6h = 30           (I)

             4c + 8h = 30.6       (ii)

From equation i, divide through by 6 to give;

           c + h = 5

           c = 5 - h

Input into equation ii;

      4(5 - h) + 8h = 30.6

      20 - 4h + 8h = 30.6

           4h = 30.6 - 20

           4h = 10.6

             h = 2.65

Price of ham sandwich = $2.65

  Now, for the chicken sandwich;

           c  = 5 - 2.65 = $2.35

Cost chicken sandwich is  $2.35

Cost of ham sandwich is $2.65