Question 1159010
 Jack brought seven tickets for a movie
 he pay seven dollars for each adult ticket
 and four dollars for each child ticket.
 Jack spent $40 for the tickets
Write a system of equations
 how many adult tickets jack bought?
:
a = no. of adult tickets
c = no. of children's ticket
:
a + c = 7
7a + 4c = 40
:
c = -a + 7
replace c in the 2nd equation, and solve for a
7a + 4(-a+7) = 40
7a - 4a + 28 = 40
3a = 40 - 28
3a = 12
a = 12/3
a = 4 adults
:
:
Check: we know that he bought 3 kid's tickets
3(4) = 12
4(7) = 28
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total 40