Question

Ch3c(ch2ch3)2(ch2)5ch3 naming

Answer 1

H3C -- C -- CH2-- CH2-- CH2-- CH2-- CH2--CH3
            |
            CH2 -- CH3

Observe the longest chain. Then start counting from the branching side. 

     1     2     3        4         5         6        7        8
H3C -- C -- CH2-- CH2-- CH2-- CH2-- CH2--CH3
            |
            CH2 -- CH3


So there are 8 carbons in the long chain means Octane.
Now, there is a ethyl group at 2nd carbon. 
So, it is 2-ethylocatane

2-ethylocatane