An animal shelter categorizes donors based on their yearly donation, as shown in the table

Question

Paula originally planned to donate $50 each month. After reviewing her budget, she decided that she must reduce her planned donation. By what amount can she reduce her originally planned minty donation of $50 so that she will be in the silver category?

Answer 1

Let's suppose that a donation of S gets you into the silver category and let's call the amount by which Paula reduces her monthly donation R.

Then we want to solve:

S ≥ 12(50 - R)

Or equivalently,

S ≥ 600 - 12R

If we know S, this can be written as:

S - 600 ≥ -12R

or equivalently,

(S - 600) / 12 ≥ - R

So:

R ≥ (600 - S) / 12

Answer 2

The answer is 50-x where x is the minimum MONTHLY amount needed to be in the silver category.

If the amount in ANNUAL, then

the formula is

50 - x/12