Question

Brand X soda advertises, "We will give you 20% more soda than Brand Y for a total price that is 10% less than Brand Y's price!" What is the ratio of the unit price of Brand X soda to the unit price of Brand Y soda? Express your answer as a common fraction.

Answer 1

let a = soda in x
let b = soda in y

let c = price of x
let d = price of y

a = 1.2b
c = 0.9d

lets look at them in similar terms. the price/soda of y is d/b, since we let it equal that.
the ratio in x is 0.9d/1.2b. reduced, this is equal to 3d/4b

therefore the ratio of x : y is (3/4) : (1/1) = 3/4 : 1

:)