If 35% of the mobile phones sold by company A during November were sold at a discount, how many mobile phones of company A were sold without a discount, during that month?

Answer: Option C

Number of mobile phones sold by A during November
$$\begin{array}{rl}& =45000\times \frac{12}{100}\times \frac{7}{15}\\ & =2520\end{array}$$
Number of phones sold by A in November without discount
$$\begin{array}{rl}& =2520\times \frac{65}{100}\\ & =1638\end{array}$$