The population of a town in three consecutive years are 5000, 7000 and 8400 respectively. The population of the town in the fourth consecutive year according to geometrical increase method is A. 9500 B. 9800 C. 10100 D. 10920

The population of the town in the fourth consecutive year is 10920.

The population of the town in three consecutive years are 5000, 7000 and 8400 respectively. This means that the population of the town is increasing by 40% each year.

To calculate the population of the town in the fourth consecutive year, we can use the following formula:

$P_n = P_0 r^{n-1}$

where:

• $P_n$ is the population of the town in the $n$th year
• $P_0$ is the population of the town in the first year
• $r$ is the rate of increase
• $n$ is the number of years

In this case, we have:

• $P_0 = 5000$
• $r = 40\%$
• $n = 4$

Substituting these values into the formula, we get:

$P_4 = 5000 \times 1.4^{4-1} = 10920$

Therefore, the population of the town in the fourth consecutive year is 10920.