The difference between the CP and SP of an article is 240. If the profit is $20\% $ then the SP is:
A. $1240$
B. $1440$
C. $1200$
D. $1600$

Hint: According to the question given in the question we have to determine the SP when the difference between the CP and SP of an article is 240. If the profit is $20\% $. So, first of all we have to use the formula to find gain percentage which is as given below:

Formula used: $ \Rightarrow $Gain%$ = \dfrac{{SP - CP}}{{CP}} \times 100$
So, we have to substitute all the values in the formula (A) above to determine the CP which is the cost price.

Complete step-by-step solution:
Step 1: First of all we have to use the formula (A) to determine the gain% hence, on substituting all the values in the formula (A) as mentioned in the solution hint.
$ \Rightarrow 20 = \dfrac{{240}}{{CP}} \times 100$………………(1)
Step 2: On applying the cross-multiplication we can obtain the cost price as from the expression (1) which is obtained in the solution step 1.
$
   \Rightarrow CP = \dfrac{{240}}{{20}} \times 100 \\
   \Rightarrow CP = 1200..............(2)
 $
Step 3: Now, with the help of the cost price as obtained in the solution step 2. We can easily determine the selling price (SP). Hence,
$
   \Rightarrow SP = 1200 + 240 \\
   \Rightarrow SP = 1440
 $
Final solution: Hence, with the help of the formula (A) we have determined the selling price which is 1440rs.

Therefore option (B) is correct.

Note: To determine the selling piece it is necessary that we have to use the formula to find the gain% so that we can obtain the cost price first.
Cost is the expense incurred for the marketing a product and price is the amount the customer is willing to pay for that product .