Answer:
The number of adults who saw a movie that day is 7 
and 
the pair of equations that can be solved to find the numbers is
6x+y = 70 
x + y = 35
Step-by-step explanation:
Let the total no. of adults who saw the move be x
Let the total no. of child who saw the move be y
Given that the total number of adults (a) and children (c) who saw a movie was 35
thus. x + y = 35
cost of ticket for 1 adult = $6
cost of ticket for 1*x  adult = $6*x = $6x
cost of ticket for x  adult = $6x
cost of ticket for 1 child = $1
cost of ticket for 1*y  child = $1*y = $y
cost of ticket for y  child =  $y
Total cost for  x adult and y child = $(6x+y)   _______(2)
Given that he total money collected was $70
Thus, we have two equations
6x+y = 70  -------(1)
x + y = 35
y = 35 - x  (using this value of y in equation 1 we have)
6x + 35 - x = 70 
=> 5x = 70 -35 = 35
=> x = 35/5 = 7
The number of adults who saw a movie that day is 7 
and 
the pair of equations that can be solved to find the numbers is
6x+y = 70 
x + y = 35