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.
