Ans is option (B)
Let the salaries of Ramesh, Ganesh and Rajesh in the year 2010 be : $6x,5x,7x$ respectively.
Let the salaries of Ramesh, Ganesh and Rajesh in the year 2015 be : $3y,4y,3y$ respectively.
Given that Ramesh’s salary increased by $25$%, we get this equation:
$3y=6x+\frac{1}{4}(6x)$ $\Rightarrow$ $y=\frac{5}{2}x$
Now, Rajesh’s salary in the year 2015 is : $3y=3\times\frac{5}{2}x=\frac{15x}{2}=7.5x$
$\therefore$ Pecentage increase in Rajesh’s Salary $=$ $\frac{7.5x-7x}{7x}\times100=\frac{100}{14}=7.142$%