First you need to find a common denominator which yours is 4. Then so for the adults the answer would be 6/4. Then you need to multiply 42 times 4 and so your fraction would be 168/4. Then you have to add the kids and the adults daily water intakes together. After you have done that you can either divide total amount of water by the kid adult water intake or you can subtract and add. If you have left overs this means you cant go another day so it would be a partial day.
