transcript:
cat mum: what's 6 times 7?
cat boy (making faces): 6 7!!!
cat mum: hilarious, as always. but actually ...?
cat boy: 42
cat mum: 6 x 7 - 6 7 - is 42?!
cat boy: yeah ... so?
cat mum (making faces): that means 6 7 is the answer to the ultimate question of life, the universe and everything!
cat boy: daddy! mommy's being weird again!
cat dad: aww, you see son, - your mommy is just a huge dork!
cat mum: history doesn't repeat itself, but it rhymes!
Earth was destroyed before it finished calculating. Of course the Question, as expressed by Arthur (who was part of said calculation), was wrong.
Never mind the issue of corrupted data from Ark B...