Problem of the Week - Middle School - Sept. 20 to Sept. 26, 2020

Middle School:

Question: On the news this morning, Haroula heard the weather person say, “Yesterday morning’s rain totaled 2.4 inches.” She is curious what 2.4 inches of rain really means. If it rained at a steady rate from 4 AM to 12 PM, use the chart below to help Haroula determine the type of rain that fell yesterday. (Use 1 inch ≈ 25 mm)

Type of Rain Rate (in mm/hr)
Light x ≤ 0.5; Moderate 0.5 < x ≤ 4.0; Heavy 4.0 < x ≤ 8.0; Very Heavy x ≥ 8.0 

Answer: Heavy Rainfall

Solution: Using 1 inch ≈ 25 mm, we find 2.4 inches ≈ 60 mm. Since there are 8 hours from 4 a.m. to 12 p.m., we can find the rate of rainfall over that time period, 60 mm ÷ 8 hours = 7.5 mm/hr. Now, we can use the chart to see 7.5 mm/hr is considered heavy rainfall.