Sara receives a 10% commission on the first $4000 in sales and 15% on all sales beyond $4000. If Sara receives a commission of $2530, how much did she sell?

Step-by-step explanation:

$4000(0.10) = $400

which is less than her paid commission

so we know that she sold more than $4000 worth

if s is sales above $4000

$2530 = 400 + 0.15s

$2130 = 0.15s

s = $14200

so total sales x is

x = $4000 + $14200 = $18200

whole numbers.

step-by-step explanation:

we are given the average monthly rainfall (in millimeters) model r(m) for the years 1900-2009 as a function of the month number m.

as we can see m is taken for the number of months for years 1900-2009.

we know that number of months can't be a negative number or decimal number or a fraction.

so, the number of months could be only positive whole numbers.

therefore, whole numbers is more appropriate for the domain of r.