Jai Bhan wanted to sell his mobilephone consists of the instrument and a SIM card, but Praveen who intended to but it, asked the price of SIM card only ? Jai Bhan told him that the price of the SIM card is Rs. 4000 less than the price of the instrument but if he wished to buy the complete set he had to pay Rs. 5000 only. The price of the instrument was :

Options

A. 5500
B. 2500
C. 4500
D. can't be determined

Answer

To solve the problem step by step, let's define the variables and set up the equations based on the information provided.

### Step 1: Define the Variables
Let:
- \( i \) = price of the instrument
- \( s \) = price of the SIM card

### Step 2: Set Up the Equations
From the problem, we have two pieces of information:
1. The price of the SIM card is Rs. 4000 less than the price of the instrument:
\[ s = i - 4000 \]
2. The total price for both the instrument and the SIM card is Rs. 5000:
\[ i + s = 5000 \]

### Step 3: Substitute the Value of \( s \)
We can substitute the expression for \( s \) from the first equation into the second equation:
\[ i + (i - 4000) = 5000 \]

### Step 4: Simplify the Equation
Combine like terms:
\[ 2i - 4000 = 5000 \]

### Step 5: Solve for \( i \)
Now, add 4000 to both sides of the equation:
\[ 2i = 5000 + 4000 \]
\[ 2i = 9000 \]
Now, divide both sides by 2:
\[ i = \frac{9000}{2} \]
\[ i = 4500 \]

### Conclusion
The price of the instrument is Rs. 4500.

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