It cost 5 dollars for a child ticket and 8 dollars for a adult ticket. total tickets sold were 110 bringing in 820 dollars? how many child tickets were bought?

Number of child tickets bought is 20

Given that It cost 5 dollars for a child ticket and 8 dollars for a adult ticket

cost of each child ticket = 5 dollars

cost of each adult ticket = 8 dollars

Let "c" be the number of child tickets bought

Let "a" be the number of adult tickets bought

Total tickets sold were 110 bringing in 820 dollars

Number of child tickets bought + number of adult tickets bought = 110

c + a = 110 ----- eqn 1

Also we can frame a equation as:

Number of child tickets bought x cost of each child ticket + number of adult tickets bought x cost of each adult ticket = 820

5c + 8a = 820 -------- eqn 2

Let us solve eqn 1 and eqn 2 to find values of "c" and "a"

From eqn 1,

a = 110 - c  ------ eqn 3

Substitute eqn 3 in eqn 2

5c + 8(110 - c) = 820

5c + 880 - 8c = 820

-3c = - 60

c = 20

Therefore from eqn 3,

a = 110 - 20 = 90

a = 90

Therefore number of child tickets bought is 20