Question 216746
Movie tickets cost $4.00 for a child and $7.00 for adults.  they collected $720.00 by selling 120 tickets.  how many adult tickets were sold?


Step 1.  Let x be the number of child tickets.


Step 2.  Let 4x be the dollar value of child tickets sold.


Step 3.  Let 120-x be the number of adult tickets.


Step 4.  Let 7(120-x) be the dollar value of adult tickets sold


Step 5.  Then,  4x+7(120-x)=720 or 4x+840-7x=720.


Step 6.  Solving yields the following:


*[invoke explain_simplification "4x+840-7x=720" ]



With x= 40, then 120-x=80


Check....total dollar value.  4*40+7*80=160+560=720...which is a true statement.


Step 7.  ANSWER:  The number of adult tickets sold is 80.


I hope the above steps were helpful. 


For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.


And good luck in your studies!


Respectfully,
Dr J