If you handle 60 emails at a rate of 15 per hour, how long does it take?

• A. 3 hours
• B. 4 hours
• C. 2 hours
• D. 5 hours

Answer: (B)

This problem hinges on using rate to find time. Time equals the total quantity divided by the rate. You have 60 emails to process at a rate of 15 emails per hour, so the time is 60 ÷ 15 = 4 hours. You can check by multiplying back: 4 hours × 15 emails/hour = 60 emails. The other options would correspond to processing a different total at that same rate (3 hours would be 45 emails, 2 hours would be 30, 5 hours would be 75), so 4 hours is the correct duration.