Answer:
The number of adults who attended=850
The number of children who attended=350
Step-by-step explanation:
a). Determine first expression
Let the number of each group be as follows;
adults=a
children=c
total number of people=1200
This can be expressed as;
number of people=number of children+number of adults
replacing;
a+c=1200...equation 1
b). Determine the second expression
Let the total cost be expressed as shown;
total cost=(cost per child×number of children)+(cost per adult×number of adults)
where;
total cost=$8,375
cost per child=$4.5
number of children=c
cost per adult=$8
number of adults=a
replacing;
(8×a)+(4.5×c)=1,200
8 a+4.5 c=8,375...equation 2
c). Combine equation 1 and 2 and solve simultaneously
1(8 a+4.5 c=8,375)
4.5(a+c=1,200)=4.5 a+4.5 c=5,400
(8 a-4.5 a)+(4.5 c-4.5 c)=(8,375-5,400)=2,975
3.5 a=2,975
a=2,975/3.5
a=850
replacing the value for a in equation 1
850+c=1200
c=1200-850=350
The number of adults who attended=850
The number of children who attended=350