$Year$ $2008$ :- Let Male$=$$M_{1}$ and Female$=$$F_{1}$
Given $\frac{M_{1}}{F_{1}}=2.5$ -------->>>Equation 1
$Year$ $2009$ :- Let Male$=$$M_{2}$ and Female$=$$F_{2}$
Given $\frac{M_{2}}{F_{2}}=3$ ---------->>>Equation 2
Given $F_{2}=2*F_{1}$ ---------->>>Equation 3
From Equation 1 : $M_{1}=2.5F_{1}$
From Equation 2 and 3 : $M_{2}=3F_{2}=6F_{1}$
So % increase in number of males=$(\frac{New value-Old value}{old value})*100$
$=(\frac{6F_{1}-2.5F_{1}}{2.5F_{1}})*100=140$%