Question 9

1. Read Values from the Graph:

   • In 2008, the ratio of male to female students is:
     $$R_{2008} = \frac{M_{2008}}{F_{2008}} = 2.5 \implies M_{2008} = 2.5 F_{2008}.$$
   • In 2009, the ratio of male to female students is:
     $$R_{2009} = \frac{M_{2009}}{F_{2009}} = 3.0.$$

2. Apply Given Condition:
   The number of female students doubled in 2009:

   $$F_{2009} = 2 \times F_{2008}.$$

3. Calculate Male Students in 2009:

   $$M_{2009} = 3.0 \times F_{2009} = 3.0 \times (2 F_{2008}) = 6.0 F_{2008}.$$

4. Percentage Increase in Male Students:

   $$\text{Percentage Increase} = \frac{M_{2009} - M_{2008}}{M_{2008}} \times 100$$
   $$= \frac{6.0 F_{2008} - 2.5 F_{2008}}{2.5 F_{2008}} \times 100$$
   $$= \frac{3.5}{2.5} \times 100 = 1.4 \times 100 = 140\%.$$

Hence, the number of male students increased by $140\%$.