Acake mix calls for these ingredients.

3 cups of milk
6 cups of flour
2 cups of sugar
1 cup of oil

which is the lowest ratio?

a. milk/flower
b. sugar/milk
c. oil/sugar
d. sugar/flower

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb