6 boys and 15 girls can do a piece of work in 4 days while 12 boys and 3 girls can do the same work in 5 days. In how many days will 1 boy and 1 girl do the same work? If 3 men or 4 women can do a piece of work in 16 days, in how many days can 12 men and 8 women do the same piece of work?