population

[ruplun]

The population of Linterhast was 3,600 people in 1990 and 4,800 people in 1993. If the population growth rate per thousand is constant, then what will be the population in 1996?

(A) 6,000
(B) 6,400
(C) 7,200
(D) 8,000
(E) 9,600

[Brent@GMATPrepNow]

The population of Linterhast was 3,600 people in 1990 and 4,800 people in 1993. If the population growth rate per thousand is constant, then what will be the population in 1996?

(A) 6,000
(B) 6,400
(C) 7,200
(D) 8,000
(E) 9,600

To calculate the growth rate, we'll use the formula: (new value - old value)/(old value)

Fortunately, the question tells us the increase over a 3-year period and asks for the population in another 3 years. So, all we need to do is calculate the 3-year growth rate.

The 3-year growth rate from 1990 to 1993 = (4800-3600)/3600 = 1200/3600 = 1/3

So, every three years, the population increases by 1/3

So, in the next 3 years, the population increase will be 1/3 of 4800 (which is 1600)

This means that the 1996 population will be [spoiler]4800+1600 = 6400 = B[/spoiler]

Cheers,
Brent

[[email protected]]

Let the population in 1996 be X

As the Growth rate per thousand is contant
3600/4800=4800/X

X= 6400