$0$$\xrightarrow[{\color{Blue} {+2}}]{{\color{Red} { 5\ sec}}}2\xrightarrow[{\color{Blue} {+2}}]{{\color{Red} { 5\ sec}}}4\xrightarrow[{\color{Blue} {+2}}]{{\color{Red} { 5\ sec}}}6\xrightarrow[{\color{Blue} {+2}}]{{\color{Red} { 5\ sec}}}8\xrightarrow[{\color{Blue} {+2}}]{{\color{Red} { 5\ sec}}}10$
So $Total\ Time = 25$ sec