If the marginal revenue is 50 and the price is Rs 75 then elasticity of demand is 4.

Answer

To determine whether the statement "If the marginal revenue is 50 and the price is Rs 75 then elasticity of demand is 4" is true or false, we can use the relationship between marginal revenue (MR), price (P), and elasticity of demand (E). The formula we will use is:

\[ MR = P \left(1 - \frac{1}{E}\right) \]

### Step-by-Step Solution:

**Step 1: Write down the known values.**
- Marginal Revenue (MR) = 50
- Price (P) = 75

**Hint:** Identify the variables you have and what you need to find.

**Step 2: Substitute the known values into the formula.**
\[ 50 = 75 \left(1 - \frac{1}{E}\right) \]

**Hint:** Use the formula correctly by substituting the values for MR and P.

**Step 3: Simplify the equation.**
Divide both sides by 75:
\[ \frac{50}{75} = 1 - \frac{1}{E} \]
\[ \frac{2}{3} = 1 - \frac{1}{E} \]

**Hint:** Simplifying fractions can help in solving the equation more easily.

**Step 4: Rearrange the equation to solve for \(\frac{1}{E}\).**
\[ \frac{1}{E} = 1 - \frac{2}{3} \]
\[ \frac{1}{E} = \frac{1}{3} \]

**Hint:** Isolate \(\frac{1}{E}\) to find its value.

**Step 5: Take the reciprocal to find E (elasticity of demand).**
\[ E = 3 \]

**Hint:** Remember that taking the reciprocal of a fraction gives you the elasticity.

**Step 6: Compare the calculated elasticity with the given elasticity.**
The calculated elasticity of demand is 3, while the statement claims it is 4.

**Hint:** Always compare your calculated results with the given values to determine the validity of the statement.

**Conclusion:**
Since the calculated elasticity of demand (3) does not match the given elasticity (4), we conclude that the statement is false.

### Final Answer:
The statement is false.