In this question, we have photons with 0.237 J and 659 nm, now we need to find out how many photons there are in this situation, we can do that by looking at the energy of one single photon with the following formula:
E = h*f, since we don't have the f (frequency), we can use the relationship of frequency with speed of light and wavelength
E = h * c/λ
h is Planck's constant = 6.626*10^-34 J*s
c is the speed of light = 3.0*10^8 m/s
λ is the wavelength = 659*10^-9 m
E = 6.626*10^-34 * (3.0*10^8/659*10^-9)
E = 3.02*10^-19 J, this is the energy of a single photon
Now we can take the total energy, 0.237 J and check how many photons we have:
0.237/3.02*10^-19 = 7.85*10^17 photons