the douglas family visits sealand and is charged $72.00 for 2 adults and 3 child tickets. the williams family also visited sealand and was charged $78.00 for 1 adult and 5 child tickets. how much would it cost the lopez family to go to sealand if they have 3 adults and 4 children

SIMULTANEOUS EQUATIONS
2a + 3c = 72
1a + 5c = 78 you need to get one of them the same so do 1a +5c=78 x2 =
2a + 10c = 156 , then 2a + 10c = 156 subtract 2a +3c= 72 which is 7c = 84 divide by 7 each side so c = 12 so a child ticket is £12 then so the same for the adults so 2a +3c= 72 x 5 = 10a + 15c =360 then do 1a + 5c = 78 x3 = 3a + 15c= 234 then 10a + 15c =360 subtract 3a + 15 c= 234 = 7a = 126 then divide by 7 each side so a = 18 so an adults ticket is £18
Then do 18 + 18 + 18 + 12 + 12 + 12 + 12 = 102 so it would cost the Lopez family £102 to go to sea-land

hope this makes sense .