Percentage of Customers Who Subscribed

During a recent promotion, a software company reported that 40% of their customers purchased a new subscription plan. After the promotion ended, 120 customers who bought the plan continued their subscription.

If the initial number of customers before the promotion was $N$, which represents the total customer base before the promotion, what was the total customer base if 40% of $N$ equals 120 customers? Please provide your answer in both decimal and fraction form.