Let the shopkeeper purchase the table at price \( p \).
Transaction with Amal:
- The shopkeeper sells the table to Amal at a profit of 20%.
- So, Amal buys it at: \[ \text{Cost Price for Amal} = 1.2p \]
- Amal sells the table at a profit of 30%: \[ \text{Selling Price by Amal} = 1.3 \times 1.2p = 1.56p \]
- Let this price be \( x \), so: \[ x = 1.56p \]
Transaction with Asim:
- The shopkeeper sells the table to Asim at a loss of 20%.
- So, Asim buys it at: \[ \text{Cost Price for Asim} = 0.8p \]
- Asim sells the table at a loss of 30%: \[ \text{Selling Price by Asim} = 0.7 \times 0.8p = 0.56p \]
- Let this price be \( y \), so: \[ y = 0.56p \]
Difference between Amal's and Asim's Selling Prices:
To find the difference in their selling prices relative to the shopkeeper's cost price: \[ \frac{x - y}{p} = \frac{1.56p - 0.56p}{p} = \frac{1.0p}{p} = 1 \]
Conclusion: The difference between the selling prices of Amal and Asim is exactly equal to the shopkeeper's cost price, that is, \( \boxed{p} \).