Constraint Television Radio Newspaper

Audience per advertisement $100,00018,00040,000$

Cost per advertisement $$2000$ $$300$ $$600$

Maximum media usage $102010$

To ensure a balanced use of advertising media, radio advertisements must not exceed $50\%$ of the total number of advertisements authorized. In addition, television should account for at least $10\%$ of the total number of advertisements authorized.

$1.$ What is optimal number of Radio units?