At a school event, 31 tickets cost Rs 7000 in total. Adult tickets cost Rs 330 and child tickets Rs 160. How many child tickets were sold?

A) 19

B) 20

C) 18

D) 21

Answer: A

Explanation: Let child tickets be x; adult tickets are total count − x, then equate revenue.
Solve 330(31 − x) + 160x = 7000; child tickets x = 19.