Most properties of a neutron star are extreme in comparison to normal stars. Which of the following properties is NOT unusual when compared to a normal star?
a. Density
b. Rotation
c. Magnetic field
d. Mass

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

i guess it’s a and b

compass can be used day and night, cloudy or sunny

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form