Total number of mobiles of models A, B and E manufactured in 2007 was?

Answer: Option C

$$\begin{array}{rl}& \text{Required Answer}\\ & =\frac{35\times 30}{100}+\frac{35\times 15}{100}+\frac{35\times 15}{100}\\ & =\frac{35}{100}\left(30+15+15\right)\\ & =\frac{35\times 60}{100}\\ & =21\text{ lakhs}\end{array}$$