4h 38min+6•(3h 15min-2h 57min)

To solve \(4 \text{h } 38 \text{min} + 6 \cdot (3 \text{h } 15 \text{min} - 2 \text{h } 57 \text{min})\), follow these steps:

1. Calculate the expression inside the parentheses: \[ 3 \text{h } 15 \text{min} - 2 \text{h } 57 \text{min} \]

   First, convert everything to minutes:

   \[ 3 \text{h } 15 \text{min} = 3 \cdot 60 + 15 = 180 + 15 = 195 \text{ min} \] \[ 2 \text{h } 57 \text{min} = 2 \cdot 60 + 57 = 120 + 57 = 177 \text{ min} \] Now subtract:

   \[ 195 \text{ min} - 177 \text{ min} = 18 \text{ min} \]

2. Multiply by 6: \[ 6 \cdot 18 \text{ min} = 108 \text{ min} \]

3. Convert 108 minutes back to hours and minutes: \[ 108 \text{ min} = 1 \text{ h } 48 \text{ min} \]

4. Add this to \(4 \text{h } 38 \text{min}\): \[ 4 \text{h } 38 \text{min} + 1 \text{h } 48 \text{min} \]

   First, add the hours:

   \[ 4 \text{ h} + 1 \text{ h} = 5 \text{ h} \]

   Next, add the minutes:

   \[ 38 \text{ min} + 48 \text{ min} = 86 \text{ min} \]

   Since \(86 \text{ min} = 1 \text{ h } 26 \text{ min}\), we convert minutes to hours:

   \[ 5 \text{ h } + 1 \text{ h} = 6 \text{ h} \] \[ 26 \text{ min} \]

Finally, the result is:

\[ 6 \text{ h } 26 \text{ min} \]