If the population of Townville went from 2105 to 1705, then the percent decrease in population is closest to ?

[GMATprofessional21]

A 19
B 21
C 22
D 23
E 24

[Brent@GMATPrepNow]

A 19
B 21
C 22
D 23
E 24

We need to convert the following to a percent: (2105 - 1705)/2105
Simplify: 400/2105
Pro tip: 400/2000 = 40/200 = 20/100 =20%

Since 2105 > 2000, we know that 400/2000 is a little bit less than 20%

Answer: A

Cheers,
Brent

[Scott@TargetTestPrep]

A 19
B 21
C 22
D 23
E 24

Solution:

We use the percent change formula: (New - Old) / Old x 100:

(1705 - 2105) / 2105 x 100 ≈ (1700 - 2100) / 2100 x 100 = -400/2100 x 100 = -400/21 ≈ 19

The negative value indicates a percent decrease. We see that the percent decrease in population is approximately 19 percent.

Answer: A