A charity event sells two types of tickets: standard tickets for $20 each and premium tickets for $50 each. The total revenue $R$, in dollars, from selling $s$ standard tickets and $p$ premium tickets is given by the equation $R=20s+50p$. If the charity aims to raise a specific amount of revenue, say $5000, and decides to sell 10 fewer premium tickets, how many more standard tickets must they sell to compensate for the decrease in premium ticket sales and maintain the $5000 revenue?