How many miles did norma jog in 1 1.5 hours

It depends on the speed she was going?

6*5.4*10^(-4)
=32.4*10^(-4)
move the decimal point, in scientific notation you only have a single digit with comma
=3.2*10^(-3)

so option A

to know if you have to increase or decrease the exponent you can write the intermediary steps out:
32.4*10^(-4)=32.4/10^4=(3.24*10)/(10*10^3)
reduce the fraction and you have the above solution