Answer:
5.9 hours, 10£
Explanation:
For the first question, you must find how long it would take 1 knitter to do all the work, and you can move on from there. Since it takes 11 knitters 7 hours, it would take 1 knitter 11 times as long, meaning it would take 7*11=77 hours for 1 knitter. Now we can divide 77 hours by 13 as 13 knitters could to it in 1/13 of the time. Dividing 77 by 13 we get 5.9 hours.
For the second question, if each person pays 9£, and there are 10 people, in total they are paying 10*9£=90£. This means that if the spit it up between 9 people instead, each would by 90£/9=10£. This means they would each have to pay 10£.