Mr. frankel bought 7 tickets to a puppet show and spent $24. he bought a combination of child tickets for $2 each and adult tickets for $4 each. which system of equations below will determine the number of adult tickets, a, and the number of child tickets, c, he bought

Let x be the number of child tickets he bought
Let y be the number of adult tickers he bought

① x+y=7 (child tickets+adult ticket=7 tickets in total)
② 2x+4y=24 (price of child tickets+price of adult tickets=$24 in total)

We may simply the second equation since all of the coefficients are divisible by 2.

① x+y=7
② x+2y=12

We can now use elimination by multiplying the second equation by -1.

② -(x+2y=12)
② -x-2y=-12

① x+y=7
② -x-2y=-12

Now putting the equations together,
-y=-5
y=5
x=2

Therefore he bought 2 child tickets and 5 adult tickets