Shoutbox

Assuming that all the boys in both situations do the puzzle at the same speed and same with the girls then:

If 6 girls and 4 boys can do it in 4 hours then 3 girls and 2 boys can do it in 8hours
so: 3g+2b=8hours and 2g+5b=8hours so 3g+2b=2g+5b and so 1g=3b so the girls can do it 3 times faster than a boy

So if 3g+2b=2200p/8h and 1g=3b then 11b=2200p/8h 1b=2200/8/11=25 so 1 boy can do 25 pieces in an hour and 1 girl is 3 times faster so 1 girl can do 75 pieces in an hour