Here are the solutions to your questions: 3. Depreciation and Profit/Loss a) The formula to find compound depreciation is: $$V_t = P\left(1 - \frac{R}{100}\right)^t$$ where $V_t$ is the value after $t$ years, $P$ is the original value, $R$ is the depreciation rate, and $t$ is the time in years. b) To find the selling price of the truck after 3 years: Step 1: Identify the given values. Original cost of truck ($P$) = NRs. 40,00,000 Depreciation rate ($R$) = 15% p.a. Time ($t$) = 3 years Step 2: Apply the compound depreciation formula. $$V_t = P\left(1 - \frac{R}{100}\right)^t$$ $$V_3 = 40,00,000\left(1 - \frac{15}{100}\right)^3$$ $$V_3 = 40,00,000(1 - 0.15)^3$$ $$V_3 = 40,00,000(0.85)^3$$ $$V_3 = 40,00,000 \times 0.614125$$ $$V_3 = 24,56,500$$ The selling price of the truck after 3 years is NRs. 24,56,500. c) To find the profit or loss percent to the businessman: Step 1: Calculate the total money spent by the businessman. Total money spent = Original cost of truck = NRs. 40,00,000 Step 2: Calculate the total money received by the businessman. Money received from selling the truck = NRs. 24,56,500 (from part b) Earnings from using the truck = NRs. 9,07,000 Total money received = NRs. 24,56,500 + NRs. 9,07,000 = NRs. 33,63,500 Step 3: Calculate the net profit or loss. Net Profit/Loss = Total money received - Total money spent Net Profit/Loss = NRs. 33,63,500 - NRs. 40,00,000 Net Profit/Loss = -NRs. 6,36,500 Since the value is negative, it is a loss. Loss = NRs. 6,36,500 Step 4: Calculate the loss percentage. $$\text{Loss Percentage} = \frac{\text{Loss}}{\text{Original Cost}} \times 100\%$$ $$\text{Loss Percentage} = \frac{6,36,500}{40,00,000} \times 100\%$$ $$\text{Loss Percentage} = 0.159125 \times 100\%$$ $$\text{Loss Percentage} = 15.9125\%$$ The businessman incurred a loss of $\boxed{\text{15.9125%}}$. 4. Currency Exchange a) A currency exchange rate is the value of one country's currency in terms of another country's currency. It indicates how much of one currency can be exchanged for a unit of another currency. b) To find how many American dollars Pemba will get for NRs. 2,15,160: Step 1: Identify the relevant exchange rate. Pemba is exchanging Nepali Rupees for American Dollars, meaning the bank is selling USD to Pemba. Bank's selling rate for 1 USD = NRs. 143.44 Step 2: Calculate the amount of USD Pemba receives. $$\text{Amount in USD} = \frac{\text{Total NRs}}{\text{Selling rate}}$$ $$\text{Amount in USD} = \frac{2,15,160}{143.44}$$ $$\text{Amount in USD} = 1500$$ Pemba will get $\boxed{\text{1500 American dollars}}$. c) To find how many Nepali rupees Pemba will get back after exchanging the American dollars on the same day: Step 1: Identify the relevant exchange rate. Pemba now has USD and wants to convert them back to NRs, meaning the bank is buying USD from Pemba. Bank's buying rate for 1 USD = NRs. 142.84 Step 2: Calculate the amount of NRs Pemba receives. Amount of USD Pemba has = 1500 USD (from part b) $$\text{Amount in NRs} = \text{Amount in USD} \times \text{Buying rate}$$ $$\text{Amount in NRs} = 1500 \times 142.84$$ $$\text{Amount in NRs} = 2,14,260$$ Pemba will get back $\boxed{\text{NRs. 2,14,260}}$.