2011 · Q110
If it is true that 'all pollutants are harmful', identify which of the following is invalid to infer from it?
general-mental-abilitylogical-reasoning
- APollutants constitute a subset of harmful things
- BNo pollutants are non-harmful
- CIf anything is harmful, it is a pollutant
- DSome pollutants are harmful
Explanation
From 'all pollutants are harmful', the converse 'if anything is harmful, it is a pollutant' does not follow and is the invalid inference. The source page's key misprinted this as (b); corrected by formal logic and an independent key.