On Monday, the pollen count was 320 grains per cubic meter. On Tuesday, the pollen count was 15% less. What was the pollen count on Tuesday?

1 Answer
Oct 28, 2016

Answer:

The pollen count on Tuesday was 272 grains per cubic meter.

Explanation:

The formula for calculating the percent change is #p = (N - O)/O * 100# where #p# is the percent change, #N# is the new value and #O# is the old value. Substituting what we know gives:

#-15 = (N - 320)/320 * 100#

Solving for #N# gives:

#-15/100 = (N - 320)/320#

#(-15 * 320) / 100 = N - 320#

#-4800 / 100 = N - 320#

#-48 = N - 320#

#320 - 48 = N#

#N = 272#