Question

The average rainfall for the first 3 days out of five days was recorded to be 0.45 inches. The rainfall on the last two days was in the ratio 2 : 3. The average of five days was 0.40 inches. What was the rainfall on the last day?
1. 0.45 inches
2. 0.39 inches
3. 9.35 inches
4. 0.30 inches

Answer 1

Correct Answer - Option 2 : 0.39 inches

Given:

Average rainfall for first 3 days = 0.45 inches

Ratio of rainfall on the last two days = 2 : 3

Formula Used 

Average = (Sum of data)/(Number of data)

Calculation 

Total rainfall in 3 days = 0.45 × 3 = 1.35 inches

Total rainfall in 5 days = 0.40 × 5 = 2

Rainfall in last 2 days = 2 - 1.35 = 0.65 inches 

Ratio of rainfall in last 2 days = 2 : 3 

⇒ 2 units + 3 units = 0.65 inches 

⇒ 1 unit = 0.13 inches

So, Rainfall on the last day = 3 units

⇒ 3 × 0.13 = 0.39 inches

∴ The rainfall on the last day was 0.39 inches.