At the city museum, child admission is $5.20 and adult admission is $8.70. on saturday, 150 tickets were sold for a total sales of $986.50. how many child tickets were sold that day?

  91 child tickets were sold

Step-by-step explanation:

Let c represent the number of child tickets sold. Then the number of adult tickets sold is (150-c) and the total revenue is ...

  5.20c +8.70(150-c) = 986.50

  -3.50c +1305 = 986.50 . . . . simplify

  -3.50c = -318.50 . . . . . subtract 1305

  c = -381.50/-3.50 = 91

The number of child tickets sold that day was 91.

9x+2y=80

7x+4y=72

-

x=popcorn

y=pretzels