Answer:
![2(1)/(6)\ hours](https://img.qammunity.org/2021/formulas/mathematics/college/susqc5xx3tjj53n48xj35ktdx1djhwkc2n.png)
Explanation:
Given
![Session\ 1: 1(1)/(6)](https://img.qammunity.org/2021/formulas/mathematics/college/5mdoppdaanzlz47cilglpogttw8e4p87n2.png)
![Session\ 2: 2(1)/(2)](https://img.qammunity.org/2021/formulas/mathematics/college/s64qzgw5fkvsdu9zydp9if9cfymio0vnfd.png)
![Session\ 3: (2)/(3)](https://img.qammunity.org/2021/formulas/mathematics/college/gp4ysugrgtk8sqnxnze3ae7bjh531d19je.png)
![Total\ Time = 6(1)/(2)](https://img.qammunity.org/2021/formulas/mathematics/college/j7igljscsizkmhpw6uvayv3ng4x0eoje4e.png)
Required
Determine the time in the last session
Represent the 4th session with x
So, we have:
![Session\ 1 + Session\ 2 + Session\ 3 + x = Total\ Time](https://img.qammunity.org/2021/formulas/mathematics/college/rasstzb59gx9julo1yqldmv72leqyd5pdc.png)
Substitute values for Session 1-3 and Total Time
Collect Like Terms
![x = 6(1)/(2) - 1(1)/(6) - 2(1)/(2) - (2)/(3)](https://img.qammunity.org/2021/formulas/mathematics/college/72znp7wsr5mfot367g3c7vq9aeb4nuo8wy.png)
Convert to improper fractions
![x = (13)/(2) - (7)/(6) - (5)/(2) - (2)/(3)](https://img.qammunity.org/2021/formulas/mathematics/college/z1zvtgcznbxd7tgpjqcfs69g7ipvl3yt0m.png)
Take LCM
![x = (39 - 7 - 15 - 4)/(6)](https://img.qammunity.org/2021/formulas/mathematics/college/cfi4zz907gk9yjiq4mylqhyou0dmshdjfr.png)
![x = (13)/(6)](https://img.qammunity.org/2021/formulas/mathematics/college/6c9r3b5hs89ris5s610sysll4ap085h2xx.png)
Convert to improper fraction
![x = 2(1)/(6)](https://img.qammunity.org/2021/formulas/mathematics/college/2vifmly8toapqfavqr7yn5e1twz3fmynrx.png)
Hence, the time left is
![2(1)/(6)\ hours](https://img.qammunity.org/2021/formulas/mathematics/college/susqc5xx3tjj53n48xj35ktdx1djhwkc2n.png)