Question

in the last year, a total of 2791 earthquakes occurred in the country. of these, 85.2% were minor tremors with magnitudes of 3.9 or less on the richter scale. how many minor earthquakes occurred in the country in the last year? round to the nearest whole number.

the number of minor earthquakes was \boxed{}. (round to the nearest whole number.)

Explanation:

Step1: Convert percentage to decimal

To find the number of minor earthquakes, we first convert the percentage \( 85.2\% \) to a decimal. We do this by dividing the percentage by 100, so \( 85.2\% = \frac{85.2}{100}=0.852 \).

Step2: Multiply total earthquakes by decimal

We know the total number of earthquakes is 2791. To find the number of minor earthquakes, we multiply the total number of earthquakes by the decimal we found in Step 1. So the calculation is \( 2791\times0.852 \).

Calculating \( 2791\times0.852 \):
\[

$$\begin{align*} 2791\times0.852&=(2800 - 9)\times0.852\\ &=2800\times0.852-9\times0.852\\ &=2385.6 - 7.668\\ &=2377.932 \end{align*}$$

\]

Step3: Round to nearest whole number

Rounding \( 2377.932 \) to the nearest whole number, we look at the decimal part. Since the decimal part \( 0.932\geq0.5 \), we round up the whole number part. So \( 2377.932\approx2378 \).

Answer:

2378