From the information given, in order to find who hikes faster, we need to determine the speed of John and Sara. The person with the greater speed hikes faster.

John's speed is determined by:
![\text{ Sp}eed\text{ = }\frac{20\operatorname{km}}{5\text{hrs}}=(4km)/(hr)]()
Sara's speed is determined by:
![S\text{peed =}\frac{25\operatorname{km}}{5}=\frac{5\operatorname{km}}{hr}]()
Since Sara's speed is greater than John's speed
Therefore, Sara hikes faster than John