help me solve

shane swims 42 laps in 26 minutes and 19 seconds. how many minutes and seconds would it take shane to swim 15 laps at the same average speed

$\begin{array}{rcll} 26\ {\text{minutes}} \text{ and } 19 \ {\text{seconds}} &=& 26\ {\text{minutes}} + \frac{19}{60}\ {\text{minutes}} \\ &=& \frac{ 26 \cdot 60 + 19 } {60 }\ {\text{minutes}} \\ &=& \frac{ 1579 } {60 }\ {\text{minutes}} \\ \end{array}$

15 laps:

$\begin{array}{rcll} t \cdot \frac{ 42\ \text{laps} } { \frac{ 1579 } {60 } \ {\text{minutes} } } &=& 15\ \text{laps} \\ t &=& \frac{ 15\ \text{laps} } { 42\ \text{laps} } \cdot \frac{ 1579 } {60 } \ {\text{minutes} } \\ t &=& \frac{ 1579 } {168 } \ {\text{minutes} } \\ t &=& 9\ {\text{minutes}} \text{ and } 24 \ {\text{seconds}} \\ \end{array}$