~Math Problems: Fraction~

1) If Worker A was to paint a house by himself, he would take 6h. If Worker B was to paint a house by himself, he would take 10h. How long did both of them take to paint the house together?


2) If Worker X was to cut the grass at a field alone, he would complete cutting the field in 9min. If Worker Y was to cut the grass by himself, he would take 12min. If Worker Z was to cut the grass by himself, he would also take 12 min. How long did the three of them take to cut the grass together?