Oil at 120°C is used to heat water at 30°C in a 1-1 co-current shell and tube heat exchanger. The available heat exchange area is S₁. The exit temperatures of the oil and the water streams are 90°C and 60°C respectively. The co-current heat exchanger is replaced by a 1-1 counter-current heat exchanger having heat exchange area S₂. If the exit temperatures and the overall heat transfer coefficients are same, the ratio of S₁ to S₂ is