Answer:
Number of adult were on the trip = 4
Number of child were on the trip = 7
Step-by-step explanation:
Let the Number of adult were on the trip = x
Let the Number of child were on the trip = y
As given,
For lunch they paid $7.50 for each adult meal and $5 for each child meal for a total of $65.
⇒7.50x + 5y = 65 ...........(1)
Also,
For dinner the family paid $10.50 for each adult meal and $5 for each child meal for a total of $77.
⇒10.50x + 5y = 77 ...........(2)
Now,
Subtract equation (2) from equation (1) , we get
10.50x + 5y - ( 7.50x + 5y ) = 77 - 65
⇒10.50x + 5y - 7.50x - 5y = 12
⇒10.50x - 7.50x = 12
⇒3x = 12
⇒x = [tex]\frac{12}{3}[/tex] = 4
⇒x = 4
Now,
Put the value of x in equation (2) , we get
10.50(4) + 5y = 77
⇒42 + 5y = 77
⇒5y = 77 - 42
⇒5y = 35
⇒y = [tex]\frac{35}{5}[/tex] = 7
⇒y = 7
∴ we get
Number of adult were on the trip = x = 4
Number of child were on the trip = y = 7
