Waves

Two sound waves travelling in the same direction have displacement $\mathrm{y}_1=\mathrm{a} \sin (0.2 \pi \mathrm{x}-50 \pi \mathrm{t})$ and $\mathrm{y}_2=\mathrm{a} \sin (0.15 \pi \mathrm{x}-46 \pi \mathrm{t})$.

How many times, a listener can hear sound of maximum intensity in one second?