Expert: Steve Holleran - 5/31/2007

Question
A folksinger held a concert. Tickets were $7 and $9. 219 people attended the concert, for which the receipts were $1839. How many of each type of ticket were sold?

what to check to see if my answer and work is right thanks!!

Answer
Hi Red,

The thing to remember about this type of problem is that there are two kinds of information to be found somewhere in there.  You have to be told something about the number of items, and also about the value of the items.

Here, if we let s = # $7 tickets sold and

               n = # $9 tickets sold,  we have :

                  s + n = 219

and,              7s + 9n = 1839

To solve, I would multiply the top equation by -7:

                 -7s -7n = -1533

                  7s + 9n = 1839

Adding,                 2n = 306     so  n = 153

Then subtracting from 219, s = 219 - 153 = 66

Checking,   7(66) + 9(153) = 1839.

I hope this matches your results

Steve Holleran