At the city museum, child admission is $5.90 and adult admission is $9.60. On Thursday,

131 tickets were sold for a total sales of $1050.40. How many child tickets were sold that day?

yee

c=number of children tickets

a=number of adult tickets

131 tickets sold means c+a=131

total is 1050.40 so 5.90c+9.60a=1050.40

elimination

for c+a=131

multily both sides by - 5.90

-5.90c-5.90a=-772.9

add that to other equation

-5.90c-5.90a=-772.9

5.90c+9.60a=1050.40 +

0c+3.70a=277.5

3.70a=277.5

divide both sides by 3.7

a=75

sub into other one

c+a=131

c+75=131

minus 75 from both sides

c=56

56 child tickets were sold that day