The first m-year moving average of the data 10, 20, 30, 40, 50 is 30. The value of $m$ is

5

The correct answer is Option (4) → 5 **

The first $m$-year moving average is the average of the first $m$ data values:

Data: $10, 20, 30, 40, 50$

We need:

$\frac{10 + 20 + 30 + 40 + 50}{m} = 30$

Check cumulative sums:

$m=3 \Rightarrow \frac{60}{3}=20$

$m=4 \Rightarrow \frac{100}{4}=25$

$m=5 \Rightarrow \frac{150}{5}=30$

Correct value: $m=5$