There is an order of 19000 quantity of a particular product from a customer. The firm produces 1000 quantity of that product per day out of which 5% are unfit for sale. In how many days will the order be completed?

The correct option is 20.

To find the number of days required to complete the customer's order, we need to calculate the actual quantity of products fit for sale produced by the firm each day, and then divide the total order by this daily rate.

Step 1: Identify the given data points.
Total quantity ordered by the customer = 19,000 units
Total quantity produced by the firm per day = 1,000 units
Percentage of products unfit for sale = 5%

Step 2: Calculate the number of unfit products produced per day.
Since 5% of the daily production is unfit for sale, we calculate the daily unfit quantity as follows:

$\text{Unfit Quantity per Day}=1000\times 5\%=1000\times 0.05=50\text{units}$

Step 3: Calculate the number of fit-for-sale products produced per day.
Subtract the unfit products from the total daily production to find the quantity that is fit for sale:

$\text{Fit Quantity per Day}=1000-50=950\text{units}$

Alternatively, since 5% of the products are unfit, 95% (100% - 5%) are fit for sale:
$\text{Fit Quantity per Day}=1000\times 0.95=950\text{units}$

Step 4: Calculate the total number of days needed to complete the order.
Divide the customer's total order quantity by the fit-for-sale quantity produced per day:

$\text{Number of Days Required}=\frac{\text{Total Order Quantity}}{\text{Fit Quantity per Day}}$

$\text{Number of Days Required}=\frac{19000}{950}=20$

Therefore, it will take 20 days for the firm to complete the order.