Let's rewrite frequency and wavelength in scientific notation:
[tex]f=1000000=1\cdot 10^6 Hz[/tex]
[tex]\lambda =10000 m= 1\cdot 10^4 m[/tex]
And then, by using the relationship between speed of a wave, frequency and wavelength:
[tex]v=\lambda f[/tex]
we can find the speed of the wave of the problem:
[tex]v=\lambda f=(1\cdot 10^4 m)(1\cdot 10^6 Hz)=1 \cdot 10^{10} m/s[/tex]
Note that such wave cannot exist in real world, because it travels faster than light! (the speed of light is [tex]c=3 \cdot 10^8 m/s[/tex])
