An electron in a Mercury atom is at the 'g' energy level and returns to the 'd' energy level. List how many possible photons may be emitted by the electron as it returns to the 'd' energy level

reserve is the answer

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