Hello Axro,
Look at the graph I posted of the typical output current from a CD4xxx.
Its max current (into a dead short) is 19mA when its temperature is 25 degrees C and its supply is 10V.
The graph shows the voltage dropped across the output transistor in the chip with load currents. With a 150 ohm load then the voltage dropped across the output transistor is 7.3V then the voltage across the 150 ohm resistor is the remainder which is 2.7V. Ohm's Law calculates the current to be 18mA, not 48.7mA and not 66.7mA.