MECH PUZZLES

1)Find the correct answer for the following puzzle?

2)There are a 5-liter jug and a 7-liter jug, and as much oil as you need. How can you measure out correctly 6 liters using only these two jugs?

3)Totaly three boxes are there: one with only nuts, one with only bolts, and one with both nuts and bolts.All three boxes are incorrectly labeled(e.g.,the 'nuts' label is on either 'bolts' box or both 'nuts and bolts' box).If only one product(one nut or bolt) is allowed to see from one box, is there a way to find correct labels for all three boxes?