Answer:
The percentage error in quantity P is 19%.
Step-by-step explanation:
It is given that,
A physical quantity P is related to four observables a, b and c as follows:

The percentage errors of measurements in a, b and c are 1%, 4% and 2% respectively.
We need to find the percentage error in quantity P. It is given by :

So, the percentage error in quantity P is 19%.