Fundraising Event Ticket Sales Calculation

A charity organization is planning a fundraising event. They have two types of tickets: General Admission tickets and VIP tickets. If a General Admission ticket costs $15 and a VIP ticket costs $40, the organization hopes to sell a combined total of $x$ tickets for a total revenue of $R$ dollars.

During a meeting, they decide that they want to sell twice as many General Admission tickets as VIP tickets. Let the number of VIP tickets sold be represented as $y$. Therefore, the number of General Admission tickets sold is $2y$. The equation representing the total revenue is given by:

R = 15(2y) + 40y

If they want to raise $2500 from ticket sales, what is the maximum number of VIP tickets ($y$) they can sell?