Casio EX-FC100 has a 9.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor . On the other hand, Pentax X-5 has a 16.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized BSI-CMOS sensor .
Pentax X-5's sensor provides 7MP more than Casio EX-FC100's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the EX-FC100 and X-5 sensor size comparison.
![Casio EX-FC100 vs Pentax X-5 Sensor Size Comparison]()
Sensor Size and Resolution Comparison image of Casio EX-FC100 and Pentax X-5 Cameras
Casio EX-FC100 and Pentax X-5 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.