Trying to find a dynamic alternative to an if/else statement in TypeScript

I am having an issue with the following question: For every hour a cyclist rides his/her bike, they will need to drink 0.5 liters of water. So if a cyclist rides for a total of 1 hour, he/she will need to drink 0.5 liters of water. If they cycle for 3 hours, it will be a total of 1.5 liters and etc.

My first thought was to use an if/else statement like this:

    export function liters(time: number): number {
       if (time === 1){
        return 0.5 liters 
      } else if (time === 1.5) {
         return 1 liters
       }
    }

  const answer = liters(1)
  console.log(answer)

But then I realized I can't keep writing if/else statements forever, especially if someone logs 100 hours of cycling. I am sure there is a better way of approaching this problem and making it dynamic. Does anyone have any recommendations? I am currently learning TypeScript, so please don't tell me the answer, I would prefer some leads or be pointed in the right direction, that way I can solve by myself. Thanks!