A patient’s daily temperature over six days averaged 100.0 degrees F. The first four days averaged 100.5 degrees F, and the last two days averaged 99.0 degrees F. What is the overall average?

A patient’s daily temperature over six days averaged 100.0 degrees F. The first four days averaged 100.5 degrees F, and the last two days averaged 99.0 degrees F. What is the overall average?

• A. 100.1 degrees F
• B. 99.9 degrees F
• C. 100.0 degrees F
• D. 100.2 degrees F

Answer: (C)

Think in terms of totals. The overall average is the sum of all six daily temperatures divided by six. The first four days contribute 4 × 100.5 = 402.0. The last two days contribute 2 × 99.0 = 198.0. Together that’s 402.0 + 198.0 = 600.0. Divide by six to get 600.0 ÷ 6 = 100.0 degrees F. So the overall average is 100.0 degrees F.

Think in terms of totals. The overall average is the sum of all six daily temperatures divided by six. The first four days contribute 4 × 100.5 = 402.0. The last two days contribute 2 × 99.0 = 198.0. Together that’s 402.0 + 198.0 = 600.0. Divide by six to get 600.0 ÷ 6 = 100.0 degrees F. So the overall average is 100.0 degrees F.