A man went to the Reserve Bank of India with Rs. 2000. He asked the cashier to give him Rs. 10 and Rs. 20 notes only in return. The man got 150 notes in all. How many notes of Rs. 10 did he receive?

Correct Answer: Option 100

Step-by-Step Explanation:

We are given the following information:

1. Total amount of money = Rs. 2000
2. The money is in the form of Rs. 10 notes and Rs. 20 notes.
3. Total number of notes received = 150

Let us define variables for the number of notes:

Let $x$ be the number of Rs. 10 notes received.
Let $y$ be the number of Rs. 20 notes received.

Formulating the Equations:

From the total number of notes, we get Equation (1):

$x+y=150$

From the total value of the money, we get Equation (2):

$10x+20y=2000$

Solving the System of Linear Equations:

We can simplify Equation (2) by dividing every term by 10:

$x+2y=200$

Now subtract Equation (1) from this simplified equation:

$(x+2y)-(x+y)=200-150$

$y=50$

Now substitute the value of $y=50$ back into Equation (1):

$x+50=150$

$x=150-50$

$x=100$

Therefore, the man received 100 notes of Rs. 10.