Translation:They used to walk more when they did not eat.
"They used to walk more when they were not eating" was accepted and I believe is better than the accepted answer. My answer preserves accepted meanings for both verbs which are both imperfect. ...."used to walk" and "were not eating".
I must respectfully disagree. If the sentence had the words "as much" at the end, I would say your translation was acceptable. However, the phrase "when they did not eat" means that they ate nothing for some indefinite time period, which theoretically could have been for months! Patently, this is absurd. This inference also begs the question: If they "walked more when they did not eat," then did they stop walking when they started to eat more again? The only way this sentence sounds natural is "They walked more when they hadn't eaten" or "They walked more when they hadn't eaten as much."
"They walked more when they hasn't eaten."
The above is the correct solution they gave me. That isn't correct. My translation was "They walked more when they hadn't eaten."
Surely if the correct translation is "when they did not eat" the Spanish should be "cuando no comieron."
No, because "ellos caminaban más cuando no comieron" would mean that one day, they were walking more, when all in a sudden, they didn't eat. If you use both tenses in a sentence, the imperfect will be used to explain the setting and the preterit will be a punctual and once-occurring action, that interrupted the setting. In that sentence, it seems that both clauses are bound and occur at the same time. One is the consequence of the other.
That would be the preterite. For this sentence both verbs must take the imperfect (if caminar had taken the preterite instead it would be "caminaron" rather than what you see).
they were walking more when they weren't eating....why isn't that acceptable?
"They were walking more when they weren't eating" was accepted Jan 10, 2014.
"They used to walk more when they did not eat."...Ah, those were the golden times in our beloved concentration camp.
Apparently this is an answer: "They used to walk more when they's not eaten."
"They would walk more when they hadn't eaten", was my reply.
The correction: "They used to walk more when they HASN'T eaten." Seriously?