To find out how much water is left in the bathtub, you can subtract the amount of water that drained out from the initial amount of water.
Start with the initial amount of water: 41.9 gallons
Then subtract the amount that drained: 6.7 gallons
So, the calculation is: \( 41.9 - 6.7 = 35.2 \)
Therefore, there are 35.2 gallons of water left in the bathtub.