A pharmaceutical company has drugs awaiting FDA approval. In order for the FDA to approve a drug for consumer use, the drug must pass through four phases of clinical trials: phase I, II, III, and IV. You are given the following information about the company's drugs that are in the approval process:

• 50% are in phase III or higher
• 70% are in phase III or lower
• 20% are in phase II or phase IV

Determine the percentage of the company's drugs that are in phase I.

• 10%
• 20%
• 30%
• 40%
• 50%