An exact constructed record supplies only (2 minutes, 10 liters). No starting amount or filling rule is given. Two candidate rules for 0 to 4 minutes are P: y = 5 × x and Q: y = 3 × x + 4, where x is minutes and y is total liters.
- Show that both rules match the supplied pair.
- Explain which candidate is proportional and why.
- Choose one other allowed input at which their outputs differ. Calculate both outputs and explain how a reading at that input would distinguish these two candidates.
- Does choosing between these two candidates prove every future reading beyond their stated domain? Explain what is still limited.
Rules, evidence and qualified claim