The table given below shows the average number of articles (A, B and C) sold by Pesto company in three different months. It also shows the percentage of article A sold by Pesto company out of the total number of articles sold in these months. Table also reflects the total number of article C sold in these months. Read the table carefully and answer the following questions.

Months	Average number of articles sold	Percentage of article A sold	Total number of articles C sold
April	100	40%	100
May	120	30%	70
June	72	25%	80

If the price of each article at which articles A, B and C sold in the month of April are Rs. 10, Rs y and Rs. (y + 20) respectively, then the total revenue generated by selling these articles in the month of April is Rs. 4100. Find the value of 3y.

The correct option is 15.

Let us break down the solution step-by-step to find the value of $3y$.

Step 1: Calculate the total number of articles sold in the month of April.
The table shows that the average number of articles (A, B, and C) sold in April is 100. Since there are three types of articles (A, B, and C), the total number of articles sold is given by:
$\text{Total articles sold}=\; 100\; *\; 3\; =\; 300$

Step 2: Find the number of individual articles (A, B, and C) sold in April.
- Article A: The table states that 40% of the total articles sold in April were of type A.
$\text{Articles of type A sold}=\; 40\%\; of\; 300\; =\frac{40}{100}*\; 300\; =\; 120$
- Article C: The table directly states that the total number of article C sold in April is 100.
- Article B: We can find the number of article B sold by subtracting the quantities of A and C from the total sold in April:
$\text{Articles of type B sold}=\; 300\; -\; 120\; -\; 100\; =\; 80$

Step 3: Set up the revenue equation.
The selling prices of articles A, B, and C in April are Rs. 10, Rs. y, and Rs. (y + 20) respectively. The total revenue generated by selling these articles is Rs. 4100. We write the revenue equation as:
$\left(\text{Quantity of A}*\text{Price of A}\right)+\left(\text{Quantity of B}*\text{Price of B}\right)+\left(\text{Quantity of C}*\text{Price of C}\right)=\text{Total Revenue}$
Substituting the values:
$(120*10)+(80*y)+(100*(y+20\left)\right)=4100$

Step 4: Solve for y.
$1200+80y+100y+2000=4100$
Combine the constant terms and the y-terms:
$3200+180y=4100$
Subtract 3200 from both sides:
$180y=4100-3200$
$180y=900$
Divide by 180:
$y=\frac{900}{180}=5$

Step 5: Calculate the value of 3y.
$3y=3*5=15$