Answer: Option C. -> 119 : 135
Number of mobile phones sold by B during July
$$\eqalign{
& = 45000\times\frac{17}{100}\times\frac{7}{15} \cr
& = 3570 \cr} $$
Number of mobile phones sold by B during December
$$\eqalign{
& = 45000\times\frac{16}{100}\times\frac{9}{16} \cr
& = 4050 \cr
& \therefore \text{Required ratio} \cr
& = \frac{3570}{4050} \cr
& = \frac{119}{135} \cr
& = 119:135 \cr} $$

Answer: Option A. -> 10000
Mobile phones of B sold during August
$$\eqalign{
& = 45000\times\frac{22}{100}\times\frac{5}{9} \cr
& = 5500 \cr} $$
Mobile phones of B sold during September
$$\eqalign{
& = 45000\times\frac{25}{100}\times\frac{2}{5} \cr
& = 4500 \cr} $$
∴ Required number of phones sold
  = 5500 + 4500
  = 10000

Answer: Option C. -> 130%
Number of mobile phones sold by A during July
$$\eqalign{
& = 45000\times\frac{17}{100}\times\frac{8}{15} \cr
& = 4080 \cr} $$
Number of mobile phones sold by A during December
$$\eqalign{
& = 45000\times\frac{16}{100}\times\frac{7}{16} \cr
& = 3150 \cr
& \text{Let 4080 = }x\%\text{ of 3150} \cr
& \text{Then,} \cr
& \frac{x}{100}\times3150 = 4080 \cr
& \Rightarrow x = \frac{4080\times2}{63} \cr
& \Rightarrow x = 129.5 \cr
& \Rightarrow x \approx 130 \cr
& \text{Required percentage = 130%}\cr} $$

Answer: Option C. -> 1638
Number of mobile phones sold by A during November
$$\eqalign{
& = 45000\times\frac{12}{100}\times\frac{7}{15} \cr
& = 2520 \cr} $$
Number of phones sold by A in November without discount
$$\eqalign{
& = 2520\times\frac{65}{100} \cr
& = 1638 \cr} $$

Answer: Option A. -> 23%
Required % increase
= $$\frac{\left(160-130\right)\times100}{130}$$
= 23.07%
≈ 23%

Answer: Option D. -> Rs 515 lakh
Total interest
= (30% of 130) + (40% of 160)
= 39 + 64
= Rs. 103 lakh
Given that,
This interest is calculated on 20% of borrowed fund.
Hence, borrowed funds
= $$\frac{103\times100}{20}$$
= Rs 515 lakh

Answer: Option B. -> Rs. 25 lakh
Interest in 1990-91
= 30% of 130
= 39 lakh
Interest in 1991-92
= 40% of 160
= 64 lakh
Hence, difference = Rs. 25 lakh

Answer: Option D. -> lower by 1.5%
Retained profit in 1990-91
= 25% of 130
= Rs. 32.5 lakh
Retained profit in 1991-92
= 20% of 160
= Rs. 32 lakh
∴ Decrease
= $$\frac{32.5-32}{32.5}$$   × 100
= 1.53%
≈ 1.5%

Answer: Option C. -> Rs. 12.8 lakh
Total dividend earned by share holder in 1991-92,
= 8% of 160
= Rs 12.8 lakh

Answer: Option C. -> 22%
Total sales in 1998 = 7890
Sales of Toshiba = 12%
= $$\frac{7890\times12}{100}$$
= 946.8
≈ 947
Total sales in 1999
= 7890 + (16.5% of 7890)
= 9191
Sales of Toshiba
= 8% of 9191
= 735
Change in sales
= 947 - 735
= 212
% change
= $$\frac{212\times100}{986}$$
= 21.5%
≈ 22%