Abdoul, this is the solution to the problem:
Goal of the club : raise at least $ 600
Price of each car : $3
Let c the number of cars that the club has to wash
In consequence, the inequality that represents this situatiion is:
Total money raised ≥ 600
Total money raised = 3c
Thus,
3c ≥ 600
(We use higher and equal symbol because the statement says "at least 600". If the statement would say, "more than 600", we shoould use >)