The displacement equations of two interfering waves are given by y...

Displacement equation of second wave can be written as,${y}_{2} = 5\left(sin\omegat + \sqrt{3}cos\omegat\right) = 10\left(sin\omegat \times \dfrac{1}{2} + \dfrac{\sqrt{3}}{2} \times cos\omegat\right) = 10\left(sin\omegat \times cos\dfrac{\pi}{3} + sin\dfrac{\pi}{3} \times cos\omegat\right)$

$= 10\sin \left(\omegat + \dfrac{\pi}{3}\right)$

As we can see, the phase difference between the waves is $0$. Therefore, resultant amplitude will be sum of the amplitudes of the waves.

So $A = {A}_{1} + {A}_{2} = 10cm + 10cm = 20cm$