What is the quotient?

The quotient is 4*10^12.
(6*10^8) / (1.5*10^-4) = 4*10^(8-(-4)) = 4*10^12
6 divided by 1.5 is 4. When the base is the same, and you're dividing, you subtract the exponents. They both have a base of 10, so 8-(-4) gives you 12. So, it would be 10^12.