If international demand for coal from India rises by 12%, that of Iron ore by 8% and copper by 15%, by how much percent will total export from India rise, assuming export of Gold and silver remain at the same level?

International demand for coal from India rises by 12%,

$$\Rightarrow$$ 112% of 149 = 166.88

For Iron ore,

$$\Rightarrow$$ 108% of 103 = 111.54

For Copper,

$$\Rightarrow$$ 115% of 75 = 86.25

Total percentage rise in exports from India is given by,

= $$\frac{(111.54 + 166.88 + 132 + 86.25 + 28) - 487}{487} \times 100$$

= $$\frac{524.37 - 487}{487} \times 100$$

= $$\frac{37.37}{487} \times 100$$

= $$7.6$$%

Hence, option D is the correct answer.