there were three possible groups given, the two groups that solved the problem both had "eureka" moments. Group 1 eureka was so bad I would definitely never want to hire them. Group 2 eureka should not really be an eureka moment for anyone over 12 years as it essentially hinges on "Multiplication is just like addition"
Although if it was me I might be removed from consideration because I would probably just send an email - what? Am I missing something here? It sounds like you want me to just copy the add function to new function mult and change the addition sign to a multiplication sign? Is that it?!?