The solution to the question how much was the total cost for the seminar is shown below:
Cost 1 = $ 340 for the total wages for the group
cost 2 =$5 x 5 employees, this is for the refreshments
cost 3 = $75 for the instructors fee
cost 4 = $250 for the supplies and others
Total cost = cost1 +cost2 +cost3 + cost 4
Total cost = $340 + ($5*5) + $75 + 250
Total cost = $690
C = -b + 12
2b - 3c = 1 1/2
2b -3(-b+12) = 1 1/2
2b + 3b -36 = 1 1/2
5b = 37 1/2
b = 37.5/5
b = 7.5
c + 7.5 = 12
c = 4.5
b = 7.5 c = 4.5
Hope this helps :)