Three times as many children as adults attended a concert on saturday. an adult's ticket cost $7 and a child's ticket cost $3. the theatre collected a total of $6000. how many people were there?

If you would like to know, how many people were at the concert on Saturday, you can calculate this using the following steps:

the number of children ... c = 3 * a
the number of adults ... a

the adult's ticket ... $7
the child's ticket ... $3

the number of people ... x = ?
c + a = x
c * $3 + a * $7 = $6000
3 * a * 3 + a * 7 = 6000
9 * a + 7 * a = 6000
16 * a = 6000     /16
a = 6000/16
a = 375 adults

c = 3 * a = 3 * 375 = 1125 children

x = c + a = 1125 + 375 = 1500 people

Result: There were 1500 people.