x= # adult tickets purchased
y= # child tickets purchased
Add the number of adults and children to equal 27. Then you need a second equation to determine cost. Adult tickets are 40 each (40*each adult), tickets for children are 30 each (30*each ticket for children). Add those to equal total cost of 930.
x+y=27
40x+30y=930
Solve for one variable in equation one, then substitute the answer in equation two.
x+y=27
Subtract y from both sides
x=27-y
Substitute (27-y) for x in the second equation.
40x+30y=930
40(27-y)+30y=930
1080-40y+30y=930
1080-10y=930
Subtract 1080 from both sides
-10y= -150
Divide both sides by -10
y=15 # child tickets purchased
Substitute y=15 into either equation to solve for x.
x+y=27
x+15=27
Subtract 15 from both sides
x=12 # adult tickets purchased
Check work:
40x+30y=930
40(12)+30(15)= 930
480+450=930
930=930
Hope this helps! :)
