Libby donated $50 during the first month of the year. If she makes three additional donations of equal amounts during the year, how much will she be need to be in the silver category

Question

Libby donated $50 during the first month of the year. If she makes three additional donations of equal amounts during the year, how much will she need to be in the silver category.

Answer 1

Let's call the total donation needed to be in the silver category S and the three additional and equal donations D.

Then 50 + 3D = S.

If S is known, you can solve for D as follows:

3D = S - 50

D = (S - 50) / 3