What is the wavelength of a wave that travels at a speed of 3.0x10^8 m/s and has a frequency of 1.5x10^16 m/s?

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.

Ineed the answers for these promblems i have

Which of the following compounds would be primarily ionic? methane, ch4, ammonia nh3, calcium chloride, cacl2, or carbon dioxide, co2