Question

A punch recipe calls for of a pint of fruit juice for each pint of soda.
The ratio of soda to fruit juice in the punch is
to
.

Answer 1

I think a number (fraction) is missing from your first sentence. Could you tell me how many pints of fruit juice are used for each pint of soda?

If you meant "a/b of a pint" of fruit juice per pint of soda, then the soda:fruit-juice ratio is 1 : (a/b) = b : a.
Example: if it's 2/5 pint of fruit juice per pint of soda, the ratio soda:juice = 1 : 2/5 = 5 : 2.